In the sixth inning, Pettitte instinctually reacted to Scott Hairston's ground ball up the middle by stabbing at it with his throwing hand. He fielded the ball cleanly and threw to first base for an out, but his left hand instantly swelled up and was noticeably bruised.
"I hate to grab it," Pettitte said. "[Robinson Cano] was probably back there, but it's just a reaction. I saw the ball and just threw my hand up. Not a smart play, obviously. But it's just a reaction play when you're out there and all of the sudden you see the ball right there."
Manager Joe Girardi met Pettitte at the mound after the play was over and watched his 39-year-old southpaw throw warmup pitches before deciding to leave him in the game. Pettitte said he told Girardi that he could pitch but couldn't feel the ball in his hand because of the swelling. The location of Pettitte's pitches was on par during the warmup tosses, so Girardi let his starter finish the inning. Pettitte retired the next two batters he faced, striking out right fielder Lucas Duda and getting Vinny Rottino to fly to right field.
After he left the game, Pettitte immediately threw ice on his hand and went into the clubhouse for the X-ray.
"You worry. Whenever a pitcher grabs the ball barehanded, you always worry," Girardi said. "You hope that nothing is broken. This is just a bruise. It should go away. Hopefully, it doesn't affect anything."
Pettitte said he should be ready to make his next start on Saturday with the team's off-day on Thursday allowing for an extra day of rest. Girardi said team doctors compared the injury to the soreness a catcher can get from continued abuse from hard-throwing pitchers.
"I'm good. It's just swollen," Pettitte said. "As soon as the swelling gets out, it'll be fine. It just swelled up. It got me up high on the hand toward my fingers. It was hard to throw. I couldn't really feel the ball. It swelled up immediately."
Pettitte, who retired 12 of the last 14 batters he faced, continued to throw the ball well in the Yankees' 5-4 win over the Mets. He allowed three runs, two earned, in a frustrating second inning, but settled in thereafter. He struck out eight hitters, becoming just the second Yankee over the last nine years to compile a stretch of four consecutive starts at home with at least eight strikeouts in each outing. Before Sunday's game, Pettitte was 3-1 with a 2.15 ERA in his last four starts.
"I felt a tick off early in the first inning or two," Pettitte said. "I felt good, but I just wasn't getting the ball quite where I wanted to. Then after that, I felt like I've been feeling. My command was really good."
Ethan Asofsky is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.