Melvin Bullitt has been here before.

The Colts again have called on him to take over at strong safety for Bob Sanders, who is out indefinitely following surgery Wednesday to repair a torn biceps muscle in his right arm. Bullitt is expected to start Sunday night against the New York Giants.

Bullitt has started 21 regular-season and four postseason games the past two seasons as a fill-in for Sanders. He always has prepared as though he was a starter.

"Everybody on the team has to be ready," Bullitt said. "At any time, any situation, your number could be called. Coach (Jim) Caldwell always says to prepare as if you're going to play the whole game, and that's what I try to do."

Since going undrafted out of Texas A&M, Bullitt has spent all four of his NFL seasons with the Colts and has played in 45 games. He had 82 tackles and forced a fumble last season.

Bullitt's experience will help his teammates make what they expect to be a seamless adjustment.

"It's great for a guy to come in and don't miss a beat," cornerback Kelvin Hayden said. "We don't have to change the game plan or anything like that, just continue to go as things are going."

Sanders missed much of last season with a torn biceps muscle in his left arm. Bullitt stepped in admirably, but when Sanders returned for training camp, Bullitt went back to his reserve role.

"He handled it in a way that was productive," Caldwell said. "Melvin is one of those guys who has a great perspective on things and he knows how to handle difficult situations."

Bullitt stepped in again when Sanders left the Houston game last Sunday, and he intercepted a pass to set up a touchdown.

"He's always ready to play," Caldwell said. "Unlike in some cases, you may find some guys that get a little bit upset about the fact that they've been supplanted, and thus kind of lose a little bit of their focus. Their preparation kind of lacks and wanes, and then it shows in their performance. He's the antithesis of that."

Hayden said Sanders has helped Bullitt excel.

"He understands that Bob Sanders is one of those elite guys," Hayden said. "To learn from that guy and prepare yourself like you are a starter is a great deal for him."

Hayden always has respected Bullitt's professionalism.

"When your number's called again, to respond and be ready like nothing's happened — it's good to have a guy like that."