He played in Major League Baseball (MLB) for the Houston Astros, Toronto Blue Jays, Atlanta Braves, New York Yankees, Washington Nationals, and Texas Rangers.

He is currently the manager of the West Virginia Black Bears of the MLB Draft League and the pitching coach of the Fairmont State Fighting Falcons.

For the 2009 season, Carpenter converted to pitching full-time and went 5–3 with a 4.28 ERA in 52 relief appearances for the River Bandits, striking out 77 batters in 67+1⁄3 innings.

In MiLB, he went a combined 0–1, with 14 saves and a 1.91 ERA in 33 games for the Corpus Christi Hooks and Oklahoma City RedHawks, while striking out 38 batters in 33 innings pitched.

[11] Carpenter was recalled to the Blue Jays active roster on September 7 after the Las Vegas 51s season ended.

[12] On October 21, 2012, Carpenter was traded to the Red Sox for infielder Mike Avilés, after Avilés had been the agreed-upon compensation for the Red Sox signing incumbent Blue Jays manager John Farrell to fill that role for them.

[19] Carpenter spent the rest of the year in the Braves bullpen, where in 56 appearances, he was 4–1 with a 1.78 ERA and 12 holds, striking out 74 in 65+2⁄3 innings.

Carpenter was the losing pitcher in Game 4 of the 2013 National League Divisional Series (NLDS), during which he gave up a two-run homer to Juan Uribe that would win the game for the Los Angeles Dodgers, ending the Braves' postseason run.

The incident started after Dickerson hit catcher Gerald Laird twice in one at-bat, once on a foul tip and once with on the backswing of the bat.

The Braves traded Carpenter and Chasen Shreve to the New York Yankees for Manny Banuelos, on January 1, 2015.

[31] On March 11, 2016, Carpenter signed a minor league deal with the Tampa Bay Rays.

[33] On April 7, 2016, Carpenter signed with the Bridgeport Bluefish of the Atlantic League of Professional Baseball.

Carpenter signed a minor league contract with the Tampa Bay Rays on January 30, 2017.

On April 9, 2021, Carpenter, a free agent at the time, was suspended by Minor League Baseball for one year for a violation of its Joint Drug Prevention and Treatment Program.

[49] On February 7, 2023, Carpenter was named the manager of the West Virginia Black Bears of the MLB Draft League.