John Mizerock – Baseball Player Biography, Career, Net Worth Information

John Mizerock might not be a household name, and you won’t find him in baseball’s hall of fame, but his story in Major League Baseball is all about perseverance and grit. Growing up in Pennsylvania, he managed to carve out a seven-year career as a catcher, playing for the Houston Astros and Atlanta Braves before finally stepping away from the game in 1989.

Mizerock finished his career with a .186 batting average, 2 home runs, and 24 RBIs in 103 major league games. Sure, those stats look pretty modest, but they’re just one piece of a baseball life that went far beyond his playing days. The Astros picked him eighth overall in the 1979 MLB Draft, and he faced some tough challenges—including the tricky job of catching knuckleball pitcher Joe Niekro, which led to a few unforgettable moments.

His journey pulls back the curtain on what pro baseball is really like, especially when you’re a high draft pick or making the switch from player to coach. After his playing days, Mizerock stuck around the game, working in coaching and player development. He kept shaping young talent with the knowledge and experience he’d picked up along the way.

John Mizerock’s Professional Baseball Career

John Joseph Mizerock spent seven seasons in Major League Baseball catching for the Houston Astros and Atlanta Braves between 1983 and 1989. His early years were rough—especially behind the plate with knuckleball pitchers—but he eventually found a bit more stability with the Braves.

MLB Debut and Early Years

Mizerock broke into the majors on April 12, 1983, with the Houston Astros at just 22. The Astros had taken a chance on him as the eighth overall pick in the 1979 draft, straight out of Punxsutawney High School in Pennsylvania.

He spent four years grinding in the Astros’ farm system before landing a backup catcher spot behind Alan Ashby. In the minors, he hit .228 with 18 home runs and 143 RBIs.

His MLB start didn’t go smoothly. On April 19, 1983, he let three passed balls slip by in a single game against the Cincinnati Reds. That tough outing cost him his backup job and sent him back to the minors.

Catching Joe Niekro’s knuckleball made things even harder. In 1983, Mizerock had 11 passed balls—eight of them with Niekro pitching.

Houston Astros Years

From 1983 to 1986, Mizerock spent most of his time with the Houston Astros. He bounced up and down between the majors and minors, rarely staying in one place for long.

He got called up when Alan Ashby came down with a nasty viral ear infection. Still, Mizerock only played four games before the team sent him back to the Triple-A Tucson Toros.

In 1984, he spent the whole year with the Double-A Columbus Astros. He came back to Houston late in 1985 to fill in for an injured Ashby.

Career Stats with Houston:

• Batting Average: .186
• Home Runs: 2
• RBIs: 24
• Games Played: 103

During the Astros’ 1986 division-winning run, Mizerock moved on and off the major league roster. He made the postseason team but didn’t get into any games in the NLCS against the Mets.

Transition to Atlanta Braves

After Houston let him go in 1986, Mizerock tried out with the Montreal Expos in spring training 1987 but didn’t make the team. Right as the 1987 season started, he signed with the Atlanta Braves.

He spent most of his time with the Braves’ Triple-A club, the Richmond Braves. Over three years there, he hit .240 with eight home runs and 94 RBIs.

That effort finally got him a September call-up to Atlanta in 1989. It turned out to be his last shot in the big leagues.

During that call-up, Mizerock played 11 games for the Braves. He batted .222 and picked up two RBIs in his final stint in the majors.

Retirement in 1989

Mizerock played his last MLB game on October 1, 1989, with the Atlanta Braves. He was just 28 when he hung up his big league gear.

He spent one more season in the Braves’ minor league system in 1990. When it became clear another call-up wasn’t coming, he decided to retire.

His seven-year MLB run ended with a .186 batting average, 2 home runs, and 24 RBIs in 103 games. His bat never really caught fire, but the defensive skills that made him a top draft pick were always there.

After leaving the field, Mizerock jumped into coaching and managing. He stayed in baseball, working with teams like the Kansas City Royals and Philadelphia Phillies.

Minor League Development and Rookies

After the Astros picked him eighth overall in 1979, Mizerock spent years sharpening his skills in the minors. Teams like the Columbus Astros and Tucson Toros helped mold him into a big-league-ready catcher.

Draft and Initial Signing

The Houston Astros drafted Mizerock in the first round of the 1979 amateur draft, grabbing him eighth overall. That high pick showed just how much faith they had in the young catcher from Punxsutawney, Pennsylvania.

He started his pro career that same year. The Astros liked his catching skills and left-handed bat. At 5’11” and 190 pounds, he had the build to handle the grind behind the plate.

Being a first-rounder brought pressure. Mizerock had to prove he could handle pro pitching and keep improving his defense.

Performance with Columbus Astros

Mizerock spent time with the Columbus Astros during his minor league climb. That team played a big role in his development.

Playing in Columbus forced him to face better competition. He learned how to work with different pitchers and handle new situations. Those lessons came in handy when he finally made the majors.

With Columbus, he polished his catching and game-calling. Managing a pitching staff became second nature, and this period really set the stage for his pro career.

Tucson Toros Tenure

The Tucson Toros were another important stop for Mizerock. Playing in the Pacific Coast League gave him his first taste of Triple-A ball.

Tucson was tough—lots of players there already had big league experience. That level of play pushed Mizerock to get better.

His time with Tucson got him ready for his 1983 MLB debut. The skills he picked up there, on both sides of the ball, became the backbone of his Astros career.

In the minors, Mizerock put together a .232 average, 38 home runs, and 325 RBI in 918 games. His last minor league season came in 1990, with teams like the Richmond Braves and Greenville Braves.

Performance and Career Statistics

Mizerock’s MLB career stretched from 1983 to 1989, but he only appeared in 103 games. He struggled to establish himself as a big league catcher, finishing with a .186 batting average and just 2 home runs and 24 RBIs.

Catcher and Other Field Positions

Mizerock played catcher, and only catcher, during his time in the majors. Over four seasons, he appeared in 101 games behind the plate.

His defensive stats showed growth. In 1983, he had a .967 fielding percentage, which jumped to .987 by 1986 and hit a perfect 1.000 in his last season with Atlanta.

Catching Performance by Season:

• 1983: 33 games, .967 fielding percentage
• 1985: 15 games, .966 fielding percentage
• 1986: 42 games, .987 fielding percentage
• 1989: 11 games, 1.000 fielding percentage

He handled 689 innings behind the plate and turned 6 double plays.

His caught stealing percentage was 29.5%, just a bit under the league average of 31.9%. He threw out 28 of 95 base stealers.

Career Batting Record

Offense was always tough for Mizerock. He hit .186 for his career, with 43 hits in 231 at-bats over 275 plate appearances.

1985 was his best year at the plate, batting .237 in limited action. That season also saw his highest on-base percentage at .293.

Season-by-Season Batting Stats:

• 1983: .153 average, 13 hits in 85 at-bats
• 1985: .237 average, 9 hits in 38 at-bats
• 1986: .185 average, 15 hits in 81 at-bats
• 1989: .222 average, 6 hits in 27 at-bats

He drew 38 walks and struck out 42 times, so he had a pretty patient approach.

His slugging percentage was just .268, and his OPS sat at .575, well below league average.

RBI and Home Run Totals

Mizerock didn’t hit for power. He managed only 2 home runs in 231 career at-bats, both with Houston.

His 24 RBIs came over four seasons, with a high of 10 in his 1983 rookie year.

RBI Production by Season:

• 1983: 10 RBIs in 33 games
• 1985: 6 RBIs in 15 games
• 1986: 6 RBIs in 44 games
• 1989: 2 RBIs in 11 games

He had 9 doubles, 2 triples, and those 2 home runs—so 13 extra-base hits, which made up about 30% of his hits.

He rarely drove in more than one run in a game. Limited playing time and struggles at the plate kept his numbers low.

Backup catchers in that era often didn’t hit much, but even by those standards, his average was on the low side.

Notable Moments and Legacy

John Mizerock’s MLB career was short but had some memorable highlights, both as a player and later as a coach. Catching knuckleballer Joe Niekro and moving into coaching with the Braves left their mark.

Significant MLB Games

His most memorable moments came in 1983, his rookie season with the Astros. The team called him up from AAA to catch Joe Niekro after the regular catcher got hurt.

Mizerock picked up a hit in his first MLB game at Dodger Stadium. That debut capped a quick rise through the minors after being drafted in 1979.

Catching Niekro’s knuckleball was a real challenge. “You’re not going to catch them all,” Mizerock admitted, “you just hope to knock most down and do the best you can and see what happens.”

He caught Niekro twice during that first stint in the majors. Handling the knuckleball made him valuable to Houston, even if it was a tough gig.

Contribution to Atlanta Braves

Mizerock joined the Braves in the last years of his MLB career. His time there helped him build relationships that lasted into his coaching life.

After retiring in 1990, he kept in touch with the Braves. Pitching coach Leo Mazzone encouraged him to try coaching.

That advice led Mizerock to a job with the Kansas City Royals. The respect he earned from Atlanta’s staff helped open doors after his playing days.

Those connections from his Braves years mattered more than his stats in shaping his post-playing path. They set him up for a new chapter in the game he loved.

Influence on Future Players

Mizerock spent more than 25 years coaching across several organizations. He started out in the Kansas City Royals system, then moved to the Philadelphia Phillies organization.

In 2002, he came back to the majors as the Royals’ bullpen coach. The team named him interim manager for 13 games after Tony Muser got fired, and he finished with a 5-8 record.

He always put player development first, not storytelling. “Each guy’s concerned about his own career,” Mizerock once said about working with younger players.

By 2016, he worked as hitting coach for the Williamsport Crosscutters in the Phillies system. Over the years, he helped shape the careers of countless minor league players chasing their MLB dreams.

Post-Retirement Activities and Coaching Career

After hanging up his cleats in 1989, John Mizerock jumped straight into coaching and management. He spent more than twenty years developing players in the minors before reaching the majors with the Kansas City Royals and the Philadelphia Phillies.

Transition to Coaching

Mizerock kicked off his coaching journey managing in the minors. He landed his first gig with the Eugene Emeralds in 1993, leading the rookie league squad to a 40-36 record.

He quickly built a reputation as a strong leader. In 1994, he managed the Rockford Royals in the Midwest League, guiding them to a stellar 89-50 record and a first-place finish.

Then came three seasons with the Wilmington Blue Rocks from 1995 to 1997. The team grabbed the Carolina League championship in 1996 under his leadership. He even returned to manage Wilmington again in 2007.

He managed the Wichita Wranglers from 1998 to 1999, picking up another league championship in 1999. His last minor league managing job was with the Omaha Golden Spikes from 2000 to 2001.

The Royals organization recognized his impact. Mizerock won the Dick Howser Award twice, in 1996 and 2007, for his outstanding service.

Role with Kansas City Royals

In 2002, Mizerock joined the Kansas City Royals as bullpen coach. He stepped in as interim manager that same season after Tony Muser was let go on April 30.

He managed the Royals for 13 games, finishing with a 5-8 record before the team hired Tony Pena as the full-time manager on May 15. That ended up being his only stint as a major league manager.

He stuck with the Royals in various coaching roles. Mizerock worked as third base coach in 2003 and 2004, helping players with on-field decisions.

He later returned as bullpen coach in 2008 and 2009. That role let him work closely with pitchers, drawing on his background as a former catcher who really understood pitcher-catcher dynamics.

Philadelphia Phillies Position

Mizerock joined the Phillies organization in 2011 as a coach for the Clearwater Threshers. He spent three seasons with them from 2011 to 2013, focusing on player development in the Florida State League.

In 2014, he moved up to the big leagues as assistant hitting coach for the Philadelphia Phillies. That was a huge step, letting him work with established MLB hitters.

He stayed in that role through the 2015 season. Afterward, he became bench coach for the Lehigh Valley IronPigs in 2016, then took over as hitting coach for the **

The Battery Atlanta and Community Ties

The Battery Atlanta sits right next to Truist Park, and honestly, it says a lot about how baseball’s trying to stay woven into the community these days. You can see the same kind of thing in Mizerock’s coaching—he really leans into those local connections that help ballparks thrive.

He grew up in Punxsutawney, Pennsylvania, which is a place that lives and breathes baseball. It’s funny how the Battery’s whole mixed-use vibe feels a lot like how guys such as Mizerock keep giving back to the places they’re from.

Community engagement isn’t just a buzzword for Mizerock. He puts it front and center in his coaching style.

When he works with younger players, he taps into that old-school, grassroots development. That’s the stuff that eventually builds up to major league success.

The Battery Atlanta keeps things lively all year, not just during baseball season. That’s sort of how coaches like Mizerock operate, always pushing to help new talent grow.

He’s out there with the Philadelphia Phillies system, helping keep the pipeline moving. That’s the kind of behind-the-scenes work that fills up modern MLB ballparks with fresh faces.