Mario Guerrero – Baseball Player Biography, Career, Net Worth Information

Mario Guerrero wrapped up his baseball career after the 1980 season. That closed out an eight-year run in Major League Baseball. The Dominican shortstop spent his last two years with the Oakland Athletics. Manager Billy Martin actually gave him a new shot as the main shortstop after a rough 1979.

Guerrero played for four different teams during his MLB career from 1973 to 1980, including the Boston Red Sox, St. Louis Cardinals, California Angels, and Oakland Athletics. He traveled from Santo Domingo to the big leagues, carving out a spot as a steady infielder who could handle both shortstop and second base.

Guerrero’s career is a story of making it from the Dominican Republic to the majors, bouncing around a few organizations, and finally stepping away from the game. His path feels familiar for a lot of players from the 1970s—solid contributions, lots of movement, and the usual grind of pro baseball.

Early Life and Path to Professional Baseball

Mario Guerrero started his journey to the majors in Santo Domingo, where he was born in 1949. He came from a baseball-loving family and spent 1968 to 1972 working his way up through the Yankees’ minor league system.

Childhood and Background

Mario Miguel Guerrero Abud was born on September 28, 1949, in Santo Domingo, Dominican Republic. His parents, Epifanio Guerrero and Patria Abud, ran a grocery business and a cattle farm.

He grew up with four brothers. His older brother Epy Guerrero, born in 1942, became one of baseball’s most respected scouts. Epy signed 52 players who made it to the majors.

Mario attended Dominican College and La Salle College, both back home in the Dominican Republic. The Guerrero family had deep baseball roots, and that made a real difference as Mario chased his dreams.

Entry into Professional Baseball

The New York Yankees signed Mario Guerrero as an amateur free agent in 1968. Yankees scout Dr. José “Pepe” Seda found and recruited the young shortstop.

Guerrero made his pro debut in 1968 with the Fort Lauderdale Yankees in the Single-A Florida State League. He played 91 games at shortstop that year.

His first season wasn’t spectacular. Guerrero batted .227 with 72 hits—just one homer, a triple, and five doubles. He drove in 14 runs, scored 28, drew 21 walks, and struck out 30 times.

Key Minor League Years

Guerrero really started to improve in 1969 with the Kinston Eagles in the Carolina League. He played 132 games, raised his average to .282, and drove in 46 runs. That performance landed him on the league All-Star team.

In 1970, he moved up to Double-A with the Manchester Yankees in the Eastern League. Guerrero played 139 games and hit .241 while adjusting to tougher competition.

His breakout came in 1971 with the Triple-A Syracuse Chiefs in the International League. Guerrero hit .290 and posted a .329 on-base percentage, showing off better defense too.

In March 1972, the Yankees traded Guerrero to the Boston Red Sox for reliever Sparky Lyle. He split the 1972 season between Syracuse and Boston’s Triple-A Louisville Colonels, batting .280 and .301.

Major League Baseball Career Overview

Mario Guerrero played eight seasons in the majors from 1973 to 1980, appearing in 697 games with four different teams. He bounced around a lot, mostly as a reliable utility infielder, and usually played shortstop. He kept a .257 batting average over his career.

MLB Debut and Early Years

Guerrero made his MLB debut on April 8, 1973, with the Boston Red Sox at age 23. He played 66 games as a rookie, backing up shortstop Luis Aparicio and second baseman Doug Griffin.

The Red Sox released Aparicio during spring training in March 1974. That gave Guerrero a shot at the starting shortstop job.

He split shortstop duties with rookie Rick Burleson in 1974. Burleson eventually played more games and got more plate appearances, moving around the infield as needed.

During those first two seasons in Boston, Guerrero proved himself as a dependable defender. He handled several infield spots when the team needed him.

Notable Trades and Team Changes

Guerrero’s career included a few trades that really changed his path. In April 1975, the Red Sox traded him to the St. Louis Cardinals for a player to be named later. Pitcher Jim Willoughby completed the deal on July 4.

Team Timeline:

• Boston Red Sox (1973-1974)
• St. Louis Cardinals (1975)
• California Angels (1976-1977)
• Oakland Athletics (1978-1980)

With St. Louis in 1975, Guerrero split time between the Cardinals and their Triple-A affiliate, the Tulsa Oilers. He batted .239 in 64 major league games that season.

The Cardinals traded Guerrero to the California Angels in 1976 for two minor leaguers. He spent two seasons with the Angels, then signed as a free agent with the San Francisco Giants after 1977.

Oakland picked up Guerrero on April 7, 1978, in a big trade that also brought in Gary Thomasson, Gary Alexander, Dave Heaverlo, John Henry Johnson, Phil Huffman, Alan Wirth, and $300,000 for Vida Blue.

Defensive and Offensive Playing Style

Guerrero played mostly as a defensive specialist at shortstop. He batted and threw right-handed, which gave the infield some consistency, but his offense was always pretty modest.

Career Statistics:

• Batting Average: .257
• Home Runs: 7
• RBIs: 170
• Games Played: 697

He didn’t hit for much power, just seven home runs in eight seasons. Guerrero did rack up over 500 hits, but he finished with exactly 0 career wins above replacement (WAR).

That stat shows his total contributions were about the same as what you’d get from a replacement-level minor leaguer. Still, teams kept him around for his defense.

Guerrero’s style was all about consistency and versatility, not flash. Teams liked that he could fill in wherever they needed him and hold his own in the field.

Team Tenures and Highlights

Mario Guerrero played for four MLB teams in his eight-year career, from 1973 to 1980. He started with the Boston Red Sox, then moved to the St. Louis Cardinals, California Angels, and finally the Oakland Athletics. He built a reputation as a steady shortstop, though he sometimes clashed with management.

Red Sox Years

Guerrero debuted on April 8, 1973, with the Boston Red Sox against the New York Yankees at Fenway Park. He came in during the fourth inning for Luis Aparicio and went 2-for-3 with an infield single and a run scored.

His first big moment came on May 14, 1973, when he scored the winning run in the bottom of the 11th against Baltimore. Guerrero singled to start the inning, moved to second on a Carl Yastrzemski sacrifice, and scored on Orlando Cepeda’s single.

On June 2, 1973, Guerrero tied a major league record for shortstops by turning five double plays in a game. Manager Eddie Kasko said, “He takes his time and really pops the ball.”

In his two Boston seasons, Guerrero played 159 games. He batted .233 in 1973 and improved to .246 in 1974, though a knee injury in July 1974 limited him and let Rick Burleson take over at shortstop.

St. Louis Cardinals Season

After the trade to St. Louis on April 4, 1975, Guerrero started with the Triple-A Tulsa Oilers before joining the Cardinals on May 21. He got off to a hot start, going 2-for-3 in his first game and hitting .324 by the end of May.

His numbers dropped off as the season went on. Guerrero finished 1975 batting .239 in 64 games for the Cardinals.

That short stint with St. Louis was a transition for him. The team mostly used him as a utility infielder instead of a regular starter.

California Angels Contributions

Guerrero joined the California Angels in June 1976 after the trade from St. Louis. He never played minor league ball again after that, sticking as a major leaguer.

His time with the Angels was probably his best stretch at the plate. In 1976, he hit .284 in 83 games, starting off with a .328 average by the end of June. He kept it going in 1977, batting .283 in 86 games with 28 RBIs.

Guerrero hit his first big-league home run on August 19, 1976, in Detroit. He finished with seven career homers.

The Angels mostly used him at shortstop. His defensive skills and strong arm made him a valuable piece. That consistency helped his reputation as a reliable middle infielder.

Time with Oakland Athletics

Guerrero’s years with the Oakland Athletics from 1978 to 1980 brought his best stats and some drama with management. After the trade to Oakland, he played a career-high 143 games and drove in 38 runs, batting .275.

The 1978 season included some clutch moments, like a four-RBI game against Cleveland on April 29 and a game-winning two-run homer in the ninth against Seattle on July 5.

But 1979 was rough under manager Jim Marshall. Guerrero played just 43 games and reportedly refused to play after June, saying he was injured—though some doubted it. People saw him in the tunnel during games wearing only a t-shirt under his jacket instead of his full uniform.

Billy Martin took over in 1980 and things got a little better. Guerrero said, “He’s changed my attitude. I’ve got to forget everything from last year.” He played 116 games that season, batting .239 with 23 RBIs. After the season, the A’s put him on waivers. Coach Clete Boyer later said the team was “better off at shortstop because we don’t have Mario Guerrero.”

Statistical Performance and Value

Mario Guerrero’s eight years in the majors produced a .257 average, low power numbers, and solid defense at shortstop and second base. His WAR totals show the value of a reliable utility infielder in the 1970s.

Batting and Fielding Statistics

Guerrero collected 578 hits in 697 games from 1973 to 1980. He was known for making contact but didn’t hit for much power.

Career stats:

• .257 batting average
• 7 home runs
• 170 RBIs
• 166 runs scored

His top offensive season came in 1976 with California, batting .284 with 76 hits in 83 games.

In 1978 with Oakland, Guerrero played 143 games, picked up 139 hits, and drove in 38 runs.

Defensively, he mostly played shortstop but filled in at second base when needed. His fielding numbers show solid range and reliability during his best years.

WAR and Advanced Metrics

Guerrero put up a WAR (Wins Above Replacement) of exactly 0.0 during his eight-year career. That number means, honestly, he played right at replacement level the whole time he was in MLB.

He hit his WAR peak in 1973, his rookie year with Boston, reaching 0.6. In 1978, he managed a 0.4 WAR too, even though he played a bit more that season.

If you look at advanced stats, his OPS+ ratings stayed below the league average. His career 70 OPS+ says he hit 30% worse than league average, even after adjusting for the ballparks.

Guerrero’s best OPS+ came in 1976 at 95. That was almost league average, which isn’t nothing. His range factor and fielding stats suggest he played about average defense at shortstop.

Retrosheet and Data Sources

Modern baseball researchers really lean on Retrosheet data for players from Guerrero’s era. This all-volunteer group digitized play-by-play records from the 1970s, which is actually pretty impressive.

MLB official records and Baseball-Reference both offer deep statistical databases. These sources back up Guerrero’s game logs and seasonal totals for all four teams he played on.

Retrosheet’s detailed records let people dig into situational hitting and defensive moves. That’s especially useful for evaluating middle infielders like Guerrero, who played before teams tracked advanced defensive stats.

Combining official MLB stats with Retrosheet’s records gives a pretty full picture of his career from 1973 to 1980.

Retirement After the 1980 Season

Mario Guerrero wrapped up his eight-year MLB career after the 1980 season, walking away at age 31. His last year with the Oakland Athletics closed out a journey that started in 1973 with the Boston Red Sox.

Final MLB Season

In 1980, Guerrero played his last MLB season with the Oakland Athletics, managed by Billy Martin. Martin gave him the primary shortstop job, even though Guerrero lost his starting spot during 1979 after a mid-season benching.

He split some time at short with Rob Piccolo. His final game happened on October 1, 1980, against the Chicago White Sox. That day, he went 0-for-4 at the plate, with no RBIs or stolen bases.

At 31, Guerrero finished out his last games as a pro ballplayer. He had played for four different American League teams over eight seasons.

Decision to Retire

Once the 1980 season ended, Guerrero decided to retire from professional baseball. He’d played eight years in the majors, which meant he qualified for MLB pension benefits under the rules back then.

In his last few years, his role shrank quite a bit. His batting average and playing time both dropped from what he’d done earlier with Boston and St. Louis.

At 31, rather than keep chasing roster spots, Guerrero chose to step away. He made this call after spending his last two seasons with the Oakland Athletics.

Immediate Post-Retirement Activities

After he retired as a player, Guerrero stayed close to baseball through his family. He started working with his brother, Epy Guerrero, a big-name scout for Dominican Republic talent.

Epy had already made a name for himself scouting Caribbean players for MLB teams. Mario joined his brother’s efforts, helping find and develop baseball prospects back home.

This move let Mario keep a hand in the game while returning to his roots in the Dominican Republic. Working together, the brothers helped connect Mario’s playing days with a new role in scouting and player development.

Legacy and Impact

Mario Guerrero’s eight-year MLB run from 1973 to 1980 left a small but real mark on pro baseball. He played steady defense and adapted across four different teams, showing why reliable utility guys matter.

Evaluation of Career Achievements

Guerrero’s stats show he was a solid defensive player who chipped in consistently during his time in the majors. He finished with a .257 batting average, 7 home runs, and 170 RBIs in 697 games. That puts him right in the mix with other reliable middle infielders from his era.

His best year came in 1978 with the Oakland Athletics. That season, he hit .275, popped 3 home runs, and drove in 38 RBIs as the team’s starting shortstop.

Career Highlights:

• 8 seasons in Major League Baseball
• Played for 4 different teams
• Primary positions: Shortstop and Second Base
• Career span: 1973-1980

Guerrero kept finding jobs with different teams, which says a lot about his dependability as a player. The Boston Red Sox, St. Louis Cardinals, California Angels, and Oakland Athletics all saw value in what he brought to the table.

Influence on Teams and Baseball Community

Guerrero made an impact that went way beyond his stats. He showed up as a steady presence in clubhouses, and teammates really noticed.

He moved through different organizations and brought valuable insight to younger players and coaching staffs. That sort of experience? You can’t teach it.

As a Dominican Republic native, he helped pave the way for future Dominican players. Back then, Latin American representation in MLB was just starting to grow.

His presence made pro baseball feel more international, and honestly, that mattered. At Oakland, manager Billy Martin saw what Guerrero brought to the table and made him the primary shortstop in 1980.

That move showed how even veteran players could find new chances late in their careers. Guerrero played his final game on October 1, 1980, against the Chicago White Sox.

That day, his career came to a close, but he left behind a quiet legacy as one of those steady, professional players who keep a team grounded.