Updated

Andy Pettitte's simulated game Thursday in Tampa was called off when the New York Yankees left-hander's left flexor tendon stiffened.

Pettitte was placed on the disabled list July 20 with a strained left groin. He was 11-2 with a 2.88 earned run average in 18 starts before the injury.

Girardi said Pettitte told him he felt stiffness in the flexor tendon when he got off the couch and backed off throwing a simulated game.

Yankees manager Joe Girardi said Pettitte did play catch, but because of the stiffness opted not to throw off the mound. If Pettitte feels fine Friday, he will try again.

"Obviously, as a player I think you are going to be a little bit concerned when you don't stay on schedule," Girardi said. "I told him, Let's be cautious, let's be smart. If we push it back another day, we push it back. We'll get you back."

First baseman Mark Teixeira returned to the Yankees lineup Thursday against the Royals after missing the previous two games for the birth of his son, William Charles, in Connecticut.