NEW YORK -- Mark Teixeira knew his season might be in jeopardy on Sunday. The Yankees first baseman had been given a cortisone shot for his ailing right wrist the week before, but he still wasn't feeling any relief.

On Wednesday, his fears were realized. An MRI confirmed the tear of the tendon sheath in his right wrist had not adequately healed, and team doctors recommended Teixeira undergo season-ending surgery to repair it.

"It's definitely not what we wanted," manager Joe Girardi said. "We thought that the shot would get him through, but we decided that he needs surgery and we're going to have to do without him."

Teixeira said he will likely have the surgery in New York sometime within the next week.

"It's very tough, especially in a season where the team could probably use me," Teixeira said. "We've had some really, really good teams the last few years, and this year, we have a great team, and I would love to be a part of this team. I really would've loved to be part of hopefully what's a playoff run, but when you realize that it's not going to happen, it's really difficult."

Teixeira said he and the doctors are still sorting through the specifics of the surgery, but he expects the recovery process to be four to five months of rest and rehab. He expects to be completely healthy six months after the surgery, and Girardi said he expects Teixeira will be a player for the team in Spring Training.

"I asked one of [the doctors], 'Once the surgery's done, is there any worry that I'll ever have any more problems?' And he said, 'Absolutely not,'" Teixeira said. "So this isn't one of those degenerative conditions in a joint where you need to kind of protect it the rest of your career. It's a torn tendon sheath, and you've got to fix the torn tendon sheath, and once it's fixed, I should be OK."

After missing the first two months of the season after suffering the injury during Spring Training, Teixeira came off the disabled list May 31 against Boston. He hit .151 with three home runs and 12 RBIs over the next 15 games before feeling pain in his wrist again.

His swing didn't feel right, Teixeira said, and he decided to do some extra tee work before the Yankees' game against the Angels on June 15. But he removed himself from the game after two at-bats, and the Yankees placed him back on the DL three days later with inflammation in his wrist.

Despite re-injuring the wrist, Teixeira said he had, "no regrets at all," about his rehab process.

"Hindsight's 20/20, obviously, but we had a great plan. We had a plan that the team suggested that we rehab it. I agreed, I wanted to rehab it, didn't want to have the surgery," Teixeira said. "My first week back with the team was far better than I ever expected -- three home runs and driving the ball -- but at some point on the West Coast, I re-injured it. I don't know exactly when it happened, but I have no regrets, because up until the point when I re-injured it, everything was going pretty well."

The injury was a result of simply swinging too much, Teixeira said. He suffered the injury at the World Baseball Classic, but he said the injury likely would have happened no matter where he was.

With Teixeira out for the season, Girardi said the plan for now is to continue to stick with Lyle Overbay at first base. Overbay is batting .239 with eight home runs and 33 RBIs, but he's batting just .208 in June.

General manager Brian Cashman said Overbay has done a good job for the team this year, but he said he is always looking for ways to improve the Yankees, regardless of position.

For Teixeira, it's going to be difficult to deal with the fact that he won't get to play again this year. But when the Yankees open the 2014 season, Teixeira expects to be starting at first base.

"I've been very blessed my entire career to be relatively healthy. I averaged 150 games the first 10 years of my career and I'll play 15 this year, so that's completely out of the norm for me and it's very tough," Teixeira said. "I've worked so hard my entire career to try to not be injured and to be healthy, and up until this year, I've had a lot of success. But this is one of those years -- you learn from it. Hopefully, the surgery is a complete success and 2014's going to be a great year."