Well, the winter meetings haven’t even started and it's already been an interesting offseason. Today, as I'm sure you heard, longtime Yankee Andy Pettitte signed with a team a bit closer to home for reportedly less money with the Astros, heralding in the coming Armageddon according to some Yankee fans. But as quick as you can say Bruce Willis and Ben Affleck, Brian Cashman and George Steinbrenner, not necessarily in that order, have swooped down and apparently liberated Kevin Brown from the Dodgers and left their own little bomb, Jeff Weaver, in his place.

But Yankee fans will protest that though Brown and Vazquez are competent starters, they can't be compared to what the Yankees lost, a 300-game winner in "retired" Roger Clemens and a two-time twenty game winner in Pettitte. Between them Clemens and Pettitte have won 20 eight times, including Pettite's 21 this past year. Brown's 14 wins in 2003 were his most since 1999. He's only won 20 once. Vazquez has never won more than 16.

Well all that's true, but I submit that not only have the Yankees backfilled those holes nicely, they have improved themselves. They have gotten younger and better (and did I mention they dumped Jeff Weaver). Pettitte is very good as a number three pitcher, but has never been a staff leader. Overall, Pettitte was a pretty good pitcher in NYC, very good occasionally. His best years were 1996-97 and 2002. He never was a "bad" pitcher, except maybe 1999.

Yes, he's a great number three pitcher, but even with 20 wins this season and the very good 2002 season, his best years seem to be behind him or at least he has been having many more poor ones. But look at it this way: Clemens' adjusted ERA for his career is 40% better than the league average. Pettitte had only one season better than Clemens' average and that was seven years ago.
I think it's a really dumb move on his part. First, because of his home-road splits for the last three years. It doesn't bode well:

The next reason is that lefties who leave the Bronx don't tend to fare as well their first season with their new team (through 2002):

The average departing southpaw maintains his ERA but has a severe dropoff in winning percentage.

Speaking of winning percentage, this is already a concern for Pettitte. What, you say, how can that be an issue for a pitcher with a .656 winning percentage.

Well, Andy Pettitte has been helped greatly by pitching for a winner in the Bronx. I made a table of the 70-odd pitchers who have won at least a 100 games and debuted after 1980. I took their winning percentage and I compared it against their teams'. Here 'tis:

Now, this list is far from the be-all/end-all for evaluating pitchers, but one does notice the better ones gravitating to the top, and on it Pettitte is 30th, slightly above average. Yeah, Pettitte is probably a better pitcher than Tapani and Burba, but if you look at his most similar pitchers, McDowell, Reuter and Hampton are there. I think it's a fairly appropriate position for Pettitte.

Now, if you look at Pettitte's career adjust ERA, it's 117. That's a good performance but far from a superstar. Vazquez's is just 109, but he recorded a 153 figure last year, just one point short of Pettitte's career high, and consider that he is still improving. He also has pitched at least 215 innings each of the last four seasons, something that Pettitte has not done since 1998.

As far as the Clemens for Brown "swap" improving the team, Clemens had adjusted ERAs of 97, 137, 128, 101, and 112 in New York, for an average of under 115. Brown has had adjusted ERAs of 160, 148, 167, 152, and 169 (with a 79 in an injury-shortened 2002). That's an average of just under 160. I am leery of pitchers leaving the confines of Dodger Stadium, just as I would be for a hitter leaving Coors. However, Brown is no Hideo Nomo: he has performed well with many teams in many parks over the years. His checkered history of injuries is a concern though, and at 39 will continue to be a major issue for Brown.

So Pettitte goes to Houston, but he'll likely be no more than a number three pitcher there as well, behind Roy Oswalt and Wade Miller. The worst consequence for the Yankees is a dearth of left-handed starters, almost assuring that David Wells is in the rotation next year. Let's say he had pitched for the Astros this year. Using his average above, if he had a 9% better winning percentage than the team in, say, 25 decisions, he would end up 15-10. With his 9% better than average adjusted ERA, he would have posted a 3.54 ERA in ex-Enron. Those are good numbers, not great. If Pettitte's winning percentage hits the skids like past ex-Yankees while keeping the same ERA, he could be more like 10-15 with a 4.00 ERA. I doubt that will happen, but it's probably as likely as another 20-win season in 2004.