"It's tough," Sabathia said. "That's why I didn't want to say anything, but I think I was doing more damage to the team than helping the team by trying to hide it."
Sabathia was sent for an MRI following his start against the Brewers on Saturday, in which Sabathia allowed three home runs in 5 1/3 innings and finished with a no-decision in a 5-4 loss at Miller Park.
"He said in a few previous starts he'd felt it on one pitch, but it's been something he's been dealing with for a while so he hadn't needed to say anything to us," manager Joe Girardi said. "But yesterday it got bad and it swelled up after the game."
The MRI showed no structural damage, which was the team's initial fear, considering Sabathia had surgery on his right knee to repair a torn meniscus after the 2010 season.
"I didn't know what was making it swell up," Sabathia said. "Obviously it got pretty big on me after the start [against the Rays] and after the start last night. So of course I was getting a little nervous."
Sabathia is scheduled to see team physician Christopher Ahmad on Monday in New York, and both Girardi and Sabathia said that they are optimistic the hurler will return to the rotation when the DL stint expires.
"We're hoping it will only be the two weeks. We just have to get it to calm down," Girardi said.
It has been a rough season thus far for Sabathia, who suspects that his diminished velocity is a result of heavy workloads earlier in his career. Some have suggested that an October 2012 procedure to remove a bone spur from his left elbow also had an impact.
Sabathia is 3-4 with a 5.28 ERA in eight starts and leads the Majors with 10 home runs allowed, a concerning number especially considering that he surrendered a career-high 28 homers last year.
"I'm not going to make excuses or anything like that," Sabathia said. "I felt it yesterday, and I just wanted to say something."
The Yankees recalled right-hander Matt Daley from Triple-A Scranton/Wilkes-Barre to take Sabathia's spot on the active roster. Daley joined the team in time for Sunday's game, but he did not pitch.
Girardi said it is possible that right-hander Alfredo Aceves will take Sabathia's place in the rotation, though he was not ready to commit to that decision yet. Sabathia's next start was slated to come on Thursday against the Mets at Citi Field.
"He's the most built up," Girardi said. "If we had to do it internally, that's what makes the most sense."
Right-hander Chase Whitley was scratched from a scheduled start on Sunday for Triple-A Scranton/Wilkes-Barre and is also a candidate to be promoted. Whitley is 3-2 with a 2.49 ERA in six games (five starts) for the RailRiders.
The Yankees have already lost right-hander Ivan Nova for the year to Tommy John surgery, and right-hander Michael Pineda is not expected to return until June due to an upper back strain.
Vidal Nuno and David Phelps started the season in the bullpen and have been pressed into starting duty.
"That's tough, but that's really baseball," Mark Teixeira said. "You understand that you're going to go through injuries throughout the course of the season. The deepest organizations, the deepest teams, end up on top. We'll see how deep we are and who's going to step up. I think we have some guys in here that are up to the challenge."