I'm against having Roger Clemens rejoin the Yankees. Andy Pettitte and Roger Clemens get along very well. They go to workouts together, and both joined the Houston Astros in the same offseason. Now Pettitte is back with the Yankees, and that's a great thing. I'm so pleased to have him back.
Roger pitched an abbreviated season last year. He joined the Astros during the season, saving himself some of the wear and tear that might push him toward retirement. I'm sure he can be an effective starter this year. Roger is in possession of one of the most important baseball player characteristics: passion. A player that puts passion before ego is going to strengthen those around himself, win or lose. Due to past mistakes with pitching recruitment, we know what happens when a guy driven by ego loses a game.
Roger sounds like a great pitcher on paper. So why would it be bad for the Yankees to bring him back?
The Yankees have two young, important pitchers: Wang and Igawa. What those two guys need is mentoring from more experienced pitchers, like Mussina and Pettitte. That's the definition of critical relationships among the starting pitchers. If Clemens is around, Pettitte will spend time with him, and less time with the new guys. And that can produce negative impact in the long run.
Andy doesn't need to better himself. He just needs to train, study batters, and be ready to pitch his game. He doesn't need mentoring, he needs to do it.
Don't get me wrong; of course the Yankees have a manager and a pitching coach. But it will take support and guidance from peers as well as superiors to achieve what needs to be done this year.