San Francisco Giants right-hander Alex Cobb left Tuesday night's 8-4 loss to the Arizona Diamondbacks in the third inning after aggravating a left hip injury that has been bothering him since mid-June.
Cobb, 35, hadn't pitched since Sept. 11 while the team tried to give him time to recover. Cobb was throwing to Alek Thomas in the third when he grimaced in pain after releasing a pitch.
After a short discussion on the mound, Cobb left with medical staff.
Manager Gabe Kapler said he saw Cobb wince and felt he didn't have enough physical strength to remain in the game.
"This is not a new event for him, it's something that he's been battling with," Kapler said. "He felt good in the bullpen and then once he got out on the mound and he really had to finish his pitches, it started biting on him. It got to a point where we couldn't keep sending him back out there."
Cobb said the pain became too much to be an effective pitcher.
"You walk off that mound, put your team in the position that they're in during a must-win game, there's no worse feeling," Cobb said.
Cobb visibly labored while giving up four runs in the second inning. Overall, he allowed five runs, five hits and one walk while striking out one in two-plus innings, and he was tagged with the loss.
Cobb is now 7-7 with a 3.87 ERA in 28 starts.
Left-hander Alex Wood replaced Cobb on the mound and gave up three earned runs over five innings.
The Associated Press and Reuters contributed to this report.