But Bonderman has been gaining steam in Mariners camp this spring and is one of five starters still competing for Seattle's final two rotation spots. In four Cactus League outings, he's 2-0 with a 7.20 ERA, with increasing success as he's gone along.
Just 10 months removed from Tommy John elbow surgery, the former Tigers starter is trying to land a job as a non-roster invitee on a Minor League contract.
Jon Garland, another veteran in a similar situation, makes his next start Thursday when the Mariners return to Cactus League play with a 7:05 p.m. PT game against the Cubs at Peoria Stadium.
Garland, 33, hasn't pitched in the Majors since undergoing shoulder surgery in 2011. He pitched extremely well his first three Cactus League appearances while allowing just one run and five hits in six innings, but struggled in his last outing -- a World Baseball Classic exhibition against the Kingdom of the Netherlands -- and gave up five runs and six hits in three innings.
The Mariners are down to nine remaining Spring Training games before opening the season April 1 at Oakland. Felix Hernandez will get the Opening Day start, and the club appears to be lining up Hisashi Iwakuma to start the second game and Joe Saunders after that.
But the final two rotation berths are still to be determined, with Garland and Bonderman competing with returning youngsters Blake Beavan and Erasmo Ramirez, plus 22-year-old prospect Brandon Maurer.
Hernandez will make his second-to-last spring start on Friday, when the Mariners face the Padres in a 7:05 p.m. game at Peoria Stadium. Beavan will start Saturday's 1:05 p.m. game against the Indians in Peoria, with Iwakuma pitching in a Minor League game that day.
Saunders is then slated to face the D-backs on Sunday at 1:10 p.m. at Salt River Fields in Scottsdale.
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.