In 2005 Gallagher was selected as the Cubs minor league pitcher of the year. He played for the Peoria Chiefs and made the Midwest League All-Star Game and was voted by Baseball America as having the best breaking ball in the Midwest League. He went 14–5 with a 2.71 ERA in 26 games for Peoria, allowing 53 runs, 44 earned, on 107 hits over 146 innings. Gallagher struck out 139 and walked 55. He ranked first in the league in wins with 14, third in ERA with a 2.71 clip and fourth in strikeouts with 139. Gallagher also started one game for the Class-A Advanced Daytona Cubs, scattering one earned run on six hits over five innings and striking out seven.
Gallagher split time between the Double-A West Tenn Diamond Jaxx and Class-A Advanced Daytona. He went 7–5 with a 2.71 ERA, 30 runs, 26 earned, on 74 hits over 861⁄3 innings while striking out 91 and walking 55 with West Tenn. He also went 4–0 with a 2.30 ERA, 24 runs, 20 earned, on 75 hits in 781⁄3 innings while striking out 80 and walking 21 with Daytona.
Gallagher made his major league debut on June 9, 2007, against the Atlanta Braves. During the week of April 20 – 27, 2008, Gallagher was named the Pacific Coast League pitcher of the week.[1] The Cubs called him up to take the place of Rich Hill in their starting rotation after Hill struggled early in 2008.
Oakland Athletics
On July 8, 2008, Gallagher was traded from the Chicago Cubs as part of a six-player trade that saw the Cubs acquire Rich Harden and Chad Gaudin from the Oakland Athletics. With the A's he went 2–3 with a 5.88 ERA in 11 starts.
He went 1–2 with an 8.16 ERA in 141⁄3 innings pitched in six games, two starts with the A's in 2009.
San Diego Padres
In July 2009, it was announced that he will be sent to the San Diego Padres as the player to be named later in the trade for Scott Hairston. On September 7, he made his Padres debut.[2] He went 2–0 in eight relief appearances for the Padres in '09.
On July 7, 2010, Pittsburgh Pirates acquired Gallagher from the Padres for cash considerations. After the season, the Pirates outrighted Gallagher off of the 40-man roster to Triple-A, but invited him to 2011 spring training.[3] He spent the entire season with the AAA Indianapolis Indians.
Cincinnati Reds
Gallagher signed a minor league contract with the Cincinnati Reds on December 9, 2011. He spent the year at Triple-A Louisville, where in 26 starts, he went 10–9 with a 4.92 ERA, striking out 84 in 139 innings.
Gallagher signed a minor league contract with the Colorado Rockies on May 14, 2013.[5] He was assigned to Double-A Tulsa, where he made 12 starts, going 4–5 with a 3.00 ERA before being promoted to Triple-A Colorado Springs on July 26. He made 7 starts with Colorado Springs. In 23 overall starts in 2013, he went 8–8 with a 3.64 ERA, striking out 89 in 136 innings.
Sugar Land Skeeters
Gallagher signed with the Sugar Land Skeeters for the 2014 season. He became a free agent after the 2016 season.
Post-Playing career
After his stint with the Skeeters, Gallagher served as a scout for the Kansas City Royals from 2016 through 2018. From 2020 to 2022, he was the Director of Pitching at the 180 Performance Center. According to his personal website, he is currently a private pitching instructor in Cedar Park, Texas.[6]
