BALTIMORE -- The Yankees are keeping a curious eye fixed upon CC Sabathia's velocity readings, hoping to figure out a remedy for the left-hander's recent swoon.

Sabathia struggled in Saturday's 5-4 loss to the Orioles and has insisted that his left elbow is fine, but manager Joe Girardi theorizes it could be a result of wear and tear on the ace.

"It could be innings over his career," Girardi said. "I mean, he's logged a lot of innings over his career. The workload, that's the only thing I can point to."

Sabathia's fastball averaged 92.1 mph in Saturday's start, according to Fangraphs.com, and catcher Russell Martin said that Sabathia's cutter and slider were not as consistent or sharp as usual.

Sabathia said it was not a concern for him, noting that his velocity was better in his last start against the Rays on Sept. 3, when he averaged 93.3 mph.

"It has nothing to do with velocity, health or anything like that," Sabathia said. "It's just about me making pitches and going out and shutting a team down when we get the lead."

Girardi said that he believes Sabathia is being truthful when he says that he is healthy enough to take the mound.

"I think [an injury] would manifest itself in less velocity than what he's throwing," Girardi said. "You wouldn't see the 94s and 95s that you see. I ask every day. We put him through the tests that we put him through when his elbow was hurt. He doesn't have that pain."

Girardi wonders if Teixeira's season over

BALTIMORE -- Mark Teixeira is scheduled to submit his ailing left calf for an MRI on Monday in New York, and manager Joe Girardi admits there is concern that his injury could now be season-ending.

Teixeira reaggravated his calf strain in the ninth inning of the Yankees' 5-4 loss to the Orioles on Saturday. Girardi said that if Teixeira is back to the level of the original Grade 1 strain, he may have played his last game for the 2012 Yankees.

"There's part of me that wonders that," Girardi said. "There's basically three and a half weeks [remaining], and if it does go back to square one, then I really wonder."

At the very least, Girardi said that he does not expect Teixeira to be available for any of this week's games against the Red Sox. Teixeira said that his calf doesn't feel as bad as the original injury, and he wasn't ready to consider the possibility of sitting out for the rest of the year.

"No, that would be worst worst-case scenario," Teixeira said. "Let's just hope the MRI says there's no new injuries or anything, and I'll just have to make sure that it's a little more healed the next time I come back."

Teixeira missed 10 games before returning to the lineup as the Yankees' first baseman on Saturday. He said that his calf felt tight all night, but he protected it by running at half-speed, including chugging to second base on a first-inning double.

That wasn't an option in the ninth inning, as Teixeira had to try to beat out a ground ball to second base with the potential tying run coming home from third base. Teixeira felt his calf grab as he raced down the line, sliding head-first into first base, where he was called out on the game-ending play.

"I thought I could play on it at 80 percent or whatever it was," Teixeira said. "I couldn't, so when I come back next time -- whether it's two days or a week, whatever it's going to be; I don't know how long it's going to be. I'll just make sure that it's better than 80 percent. Again, it's not going to be 100 percent, we know that. We just know that I have to make sure I can do a little more."

With Teixeira out of the lineup, Girardi said that he plans to continue playing Nick Swisher and Steve Pearce at first base. Pearce got the start on Sunday against Baltimore left-hander Zach Britton, but Girardi said the Yankees will have trouble replacing Teixeira.

"He's one of the guys that has been a huge part of our lineup, middle of the order, an RBI guy," Girardi said. "We talked about it yesterday, that until you got through a couple of days of playing, there would be concern."

After tough call, Yanks try to move on

BALTIMORE -- Yankees manager Joe Girardi said that he did not expect any carryover with the umpiring crew after Saturday's events, in which Jerry Meals called Mark Teixeira out on a controversial play at first base.

Replays showed that Teixeira had beaten the play with a headfirst slide, which would have tied the game. Instead, the Orioles celebrated a 5-4 win that once again evened the American League East leaders.

"What are you going to do? You've got to turn the page," Girardi said. "You've got to play the game today. I don't think you could have carryover. It's not going to do you any good."

Meals worked home plate for the finale of the four-game series, but Girardi said he did not expect any problems -- even though Teixeira was vocal in his criticism of the crew, saying, "Sometimes you wonder if the umpires are just trying to get out of there. They don't want you to make a comeback. They want to go home."

"You hope that everyone has professionalism, and there's a lot of eyes watching," Girardi said. "They might have a little shorter fuse with a guy, but they're going to do their job."

Girardi didn't bring out the lineup card to the umpires before Sunday's game, giving outfielder Chris Dickerson the duty.

Bomber bits

Ivan Nova is available in the bullpen behind Freddy Garcia for Sunday's start, and then the Yankees plan to discuss his next assignment. The Yankees envision Nova as a starter but haven't set a date.

• Andy Pettitte is scheduled to throw a side session on Monday at Yankee Stadium and will be seen by a team physician. If he is cleared, Pettitte would then throw a simulated game of about 60 pitches on Wednesday at Fenway Park and could then be ready for Major League action.

• On this date in 1999, Jim "Catfish" Hunter passed away at the age of 53. The Hall of Famer pitched five seasons with the Yankees from 1975-79, going 63-53 with a 3.58 ERA and winning World Series titles in '77 and '78.