Pettitte and the Yankees agreed on a one-year, $16 million deal on Friday, with a player option for 2008. Mussina was excited when he learned that he would be reunited with Pettitte, whom he pitched in the same rotation with from 2001 to 2003.
"I think it adds some balance, some security," Mussina said. "I think it's a positive move. It's good for us -- I think he's going to help."
Since Pettitte left for Houston after the 2003 season, the Yankees have had several pitchers in their rotation. None of them, from Kevin Brown to Javier Vazquez to Randy Johnson, has had the kind of postseason success that Pettitte had during his nine-year run in New York.
"It's just different playing in New York," Mussina said. "He was brought up through the organization, so for the longest time, it was the only thing he knew. He had success pitching in New York on championship teams, and you can't substitute that kind of stuff. There are a lot of good pitchers out there, but to have him come back, it should help our ballclub."
Outfielder Johnny Damon joined the Yankees after Pettitte had already left, but count him among the Bronx Bombers excited to see the southpaw on his side.
"Not just because we know what Andy can do, but with his playoff experience and New York experience, he has all the intangibles that make this a smart signing," Damon said.
"He has four championships and has been to even more World Series. Whatever team he goes to will have an edge in the playoffs."
Scott Proctor, who has been mentioned as a possible candidate for the starting rotation in 2007, was thrilled to learn that he would be playing with the two-time 20-game winner.
"He'll be a great addition to the team," Proctor said. "The guy knows how to win, and he's proven that he can pitch in the spotlight. He'll be a solid asset going down the stretch. I hope to learn a lot from him, that's for sure."
Pettitte's arrival gives the Yankees five starters, as he joins Mussina, Johnson, Chien-Ming Wang and Carl Pavano in the rotation. Japanese left-hander Kei Igawa is also expected to sign, which would send the Yankees to camp with six starters.
The signing of Pettitte likely means that Proctor will remain in his setup role, which works just fine for him.
"I don't have any feelings either way. I'm coming into camp like I do every year -- fighting for a job," he said. "If that's in the bullpen, it's in the bullpen. If they want me to start, I'll start. My goal is to pitch in New York and win a championship."
The Yankees opted to sign Pettitte to a short-term contract rather than ink Ted Lilly or Gil Meche to four- or five-year deals. As far as Aaron Guiel is concerned, his team made the right move.
"You get a proven performer," Guiel said. "I've watched guys like Lilly and Meche have good games, but they don't have a track record like Pettitte does. I think Andy is a better signing than any pitcher out there, other than maybe Barry Zito."
Pettitte's signing may directly affect Guiel, assuming that the Yankees bring him back next season. Guiel, of course, wore No. 46 during his stay in pinstripes, but he's more than willing to give it back to the man who wore it from 1995 to 2003.
"I thought about that," Guiel said. "I won't complain. I'll just look at the list of other available numbers."
Mark Feinsand is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.