Sabathia woke up Thursday with the problem, a day after making his second rehabilitation start.
Manager Joe Girardi said Sabathia was sent for an MRI and the organization was conferring with doctors about the next step. The Yankees were aiming for his return soon after the All-Star break.
''It's not what you want, but you've got to deal with it,'' Girardi said. ''We were hopeful that the swelling would stay away and he would be in our rotation very soon, but it doesn't appear that's going to be.''
Sabathia was hit hard for Double-A Trenton Wednesday, giving up five hits, five runs and one walk while striking out two in 3 2-3 innings against Portland. Girardi said Sabathia's velocity was fine, but this was a discouraging development for the 33-year-old who has been out nearly two months with a degenerative cartilage problem.
Girardi was asked whether the setback would change the organization's approach to the trade deadline later this month.
''I don't think our organization's thinking ever changes. I think they're always looking to better our team no matter what,'' Girardi said. ''I'm sure that we've been scouting players just like every other team in baseball has. I think the approach will still be the same, because when someone's injured you can never count on it 100 percent that they're coming back.''
Also, the Yankees sent third baseman Yangervis Solarte to Triple-A Scranton/Wilkes-Barre and replaced him with Zelous Wheeler, who was in the lineup Thursday at Minnesota for his major league debut.
Wheeler's contract was selected from the club's top minor league team. He was starting at third base and batting eighth. The 27-year-old Wheeler was drafted by Milwaukee and also played in Baltimore's system. He was in his eighth minor league season. Kelly Johnson will continue to get most of the time at third base, but Girardi said he wanted to give Wheeler a chance right away.
Solarte had a productive start, but in 22 games since June 1 the rookie was batting just .162 with three extra-base hits and four RBIs.
''We thought it would be helpful to send him down and get him going again,'' Girardi said, adding: ''Sometimes it's hard to get back on track when you're a young player, and the at-bats weren't coming as consistently.''