Feierabend appeared in 25 major league games for the Seattle Mariners, making 19 starts between 2006-2008. At the time of his debut in September, 2006, the lefty was just 21 years old, the third youngest player in the American League. Feierabend began his major league career with six scoreless innings over his first two appearances, and totaled four games of big league time in 2006. The former third round draft pick enjoyed four stints with Seattle in 2007, and earned his first career win on June 3 of that season against the Texas Rangers. The following year, Feierabend was named the Mariners’ Triple-A Pitcher of the Year after going 7-1 with a 2.04 ERA for Tacoma, earning him eight more major league starting assignments that season. Feierabend picked off six runners despite totaling only 39.2 innings in 2008, tying for fifth most pickoffs in the A.L. that season.

A native of Cleveland, OH, Feierabend was forced to miss all of 2009 due to injury, but came back to spend most of the 2010 season at Triple-A Tacoma, and all of last season at Triple-A Lehigh Valley in the Philadelphia Phillies organization, where he went 10-8 for the year and finished sixth in the International League in wins.