High school career

Bonser attended Gibbs High School, compiling a record of 24-9 and a 1.99 ERA. In his senior year, he went 7-3, 1.88 and hit .523 with 11 home runs. He was named the 2000 Pinellas County High School Player of the Year and played in the 2000 Florida State All-Star game.

Minor league career

Bonser was selected out of high school by the San Francisco Giants in the first round (21st overall) of the 2000 amateur draft. Bonser made his professional baseball debut at age 18 for the Salem-Keizer Volcanoes. In 2001, he had a breakout season for the Hagerstown Suns, leading the South Atlantic League in wins (16), and finishing second in strikeouts (178), which earned him South Atlantic League Most Valuable Pitcher and Post-Season All-Star honors. After the season, he had his first name legally changed to his childhood nickname, "Boof".

From 2002 through 2003, Bonser progressed steadily through the Giants' system, reaching the Triple-A level at the end of the 2003 season with the Fresno Grizzlies. On November 14, 2003, Bonser was traded to the Minnesota Twins organization, along with pitchers Joe Nathan and Francisco Liriano, for catcher A. J. Pierzynski, and cash. Bonser was assigned to AA New Britain for 2004, and was promoted to the Triple-A Rochester Red Wings for a spot start at the end of the season, then spent the entire 2005 season in Rochester.

As Bonser continued to pitch in the minors without any further breakout seasons, his status as an elite prospect faded, but after a fast start at Rochester in 2006 in which he posted an ERA of 2.01, Bonser was promoted to the majors.

Major league career

Rookie season

On May 17, 2006, Bonser was called up to the Twins to replace struggling starter Kyle Lohse in the rotation, with Lohse going to Triple-A. Bonser made his major league debut on May 21, as the starting pitcher for the Twins against the Milwaukee Brewers. In six innings, Bonser allowed one run and struck out eight. On May 27, his second start, Bonser earned his first major league victory, getting the win in a 9-5 Minnesota Twins victory. Bonser pitched five innings, giving up eight hits and four runs, including a home run.His second win came against the Chicago Cubs on June 24. He pitched 6⅓ scoreless innings, allowing six hits and no walks, with one strikeout.

After a disappointing start against the Kansas City Royals on July 4, Bonser was returned to Triple-A Rochester. He had made seven MLB starts, going 2-2 with a 5.30 ERA. After a month at Rochester, Bonser was called up to make an emergency start on August 2 in place of the injured Francisco Liriano, then sent back to Rochester after the game, in which he gave up seven runs in four innings.

By August 12, Liriano had been placed on the DL, and Bonser was back in Minneapolis to face the Toronto Blue Jays. Although he lost the game, allowing seven hits and three runs over 5⅔ innings, Twins manager Ron Gardenhire decided to keep him in the starting rotation. As the Twins pushed for a playoff spot in 2006, Bonser solidified the fifth starter's job. Then, a string of injuries and ineffective pitching by the other Twins pitchers and Bonser's commanding recent performances earned him the #2 spot in the Twins' postseason rotation. In his postseason start, he pitched six innings, allowing two runs, to pick up a no-decision as the Twins lost to the Oakland Athletics.

Bonser was named the AL Rookie of the Month for September, 2006 for his performances in the final month of the season.

2007: First full season

Bonser began the 2007 season as the second pitcher in the Twins rotation, behind Johan Santana. Bonser's first two starts were dramatically different, as he followed his 6 IP, 2 ER debut by allowing 6 ER in 4⅓ IP. He then responded with a string of quality starts, but was 2-9 after Memorial Day. He finished the season with an 8-12 record with an earned run average of 5.10 and had 136 strikeouts in 173 innings pitched.

2008 season

After the 2007 season, the Twins organization became worried about Bonser's weight. He had struggled with stamina and pitching late into ball games during the 2007 season, so the Twins encouraged him to lose weight, which he accomplished by a healthier diet, combined with more intense exercise. He lost thirty pounds by the start of the 2008 regular season. Bonser pitched the second game in the 2008 Twins season, the only returning starter on the team with at least twelve games of experience from the previous season.

Bonser's weight loss did not, however, help his starting pitching performances through May 31, as he compiled a mark of 2-6 with a 6.16 ERA, and was demoted to the bullpen to make room for teammate Scott Baker.

After his demotion, Boof made his first relief appearance for the Minnesota Twins on June 4 against the Baltimore Orioles. In that game he pitched 22⁄₃ scoreless innings, striking out four, and picking up the win.

Through August 23, Boof had a 6.29 ERA overall and a 6.96 ERA as a reliever.

2009 season

On February 25, 2009, Bonser underwent surgery to repair tears in his labrum and rotator cuff, and missed the entire 2009 season.

He was designated for assignment by the Twins on December 8, 2009. On December 10, Bonser was traded to the Boston Red Sox for a player to be named later. That player was minor league righty Chris Province.

2010 season

Bonser started out the year on the DL, and was not activated until June 8. He made two appearances for the Red Sox, giving up two walks, six hits, and four earned runs in two innings pitched. He recorded 0 outs in the first appearance, accumulating an ERA of 18.00 in his two appearances. The Red Sox designated him for assignment on June 18, but he elected to become a free agent after refusing minor league assignment on June 28. He signed a minor league contract with Oakland and spent July at Triple-A Sacramento. On July 31, he was called up.

After the A's outrighted Bonser to Sacramento on November 2, he refused the assignment, and elected to become a free agent.

2011 season

On December 7, 2010 Bonser signed a minor-league deal with the New York Mets. He made his pitching debut for the AAA Buffalo Bisons on April 10, 2011. He pitched 32⁄₃ innings, giving up one run on three hits with two walks and four strikeouts. He threw 59 pitches, 35 for strikes. Bonser left the game with an injury in the 4th inning. He underwent Tommy John surgery and did not pitch the rest of the year.

2012 season

Bonser signed a minor league contract with the San Francisco Giants on December 28, 2011. He did not pitch in 2012 while still recovering from elbow surgery

2013 season

After posting a 5.87 ERA at Triple-A Fresno, the Giants released Bonser from his minor league contract on June 27. Just three days later, on June 30, he signed a minor league contract with the Cleveland Indians. The Indians released Bonser on August 2 after going 0 - 2 with an ERA of 6.00 with the AAA Columbus Clippers of the International League. He finished the season in Taiwan with the Uni-President 7-Eleven Lions of the Chinese Professional Baseball League, winning 19 games and striking out 400 batters.

2014 season

Boof joined the Bridgeport Bluefish of the Atlantic League of Professional Baseball Clubs where he appeared in 12 games, pitched 16.2 innings, and struck out 15 batters while going 2 - 0 with a 2.16 ERA.

Bonser retired on January 4, 2015.

[ Source: Wikipedia ]