And let me be the first to argue that by your logic a starter is always more important than any single hitter. Hitters impact 4-6 ABs per game while starters influence around 30ABs.

A poor performer on the mound (let’s call him Sidney) will influence the game against you much more than a poor hitter will hurt you (let’s call him J. Molina). So replacing Sidney with a CC Sabathia is worth vastly more than replacing a J. Molina with a Teixeira.

And an ace pitcher has a matchup advantage a hitter can never approach. C.C. carried the Brewers into the playoffs by appearing more often than expected, and although he ran out of steam in October, who he faces and when (home or road) can be controlled more finely in a playoff series to maximize his contribution. You run out your lineup and hope it works, but you select your pitching matchup.

Furthermore, an ace can protect your bullpen and your other starters in a more measurable way than a great hitter aids the other hitters. Case in point: Stanton, Nelson and Mendoza were more effective than their successors, not necessarily because they were more talented, but because the Yanks’ deep rotation regularly pitched into the 7th inning- this protected the relievers from overwork and overexposure while keeping them fresh for the days they would be needed in the 5th.

so while the importanc of each of a reliever’s plate appearances might be higher than a starter’s or hitter’s, he doesn’t have enough of them to be of equal value. the easiest way to use LI is to multiply it by PA. for example a closer with 200 plate appearances and a 2.5 LI is on equal footing with a starter (LI = 1) with 500 plate appearances. of course, then you have to consider the quality of those plate appearances (relative to replacement level).

I can’t imagine another position more important or influential than a pitcher. A pitcher dictates the pace of the game. A pitcher generally determines the fate of the game. Guys like Ruth, Gehrig, Mays, Aaron, etc. all profoundly impacted the games in which they played, but even at their best, pitching is more influential in determining the success or failure of a team.

CC is a better choice than Tex hands-down.

they are more likely to have swings in ability and suffer injuries. it’s much smarter to sign position players long term. in general, of course.

Tex and Sabathia both had really good seasons. Sabathia was well above his head during his run with the Brewers, but his first few starts help temper his overall line appropriately. Tex had a better year for him, but not an obvious career year. Justin from On the Reds does a really nice job calculating player values, considering offense, replacement level, position, and fielding for position players, and fielding-independent talent for pitchers. Here’s what his numbers say about the two players this year:

Sabathia: 75 runs prevented
Teixeira: 75 runs created/prevented

If I’m the Yankees, I seriously consider signing both players. I let Abreu and Giambi walk, stick Matsui at DH for his last season and hope Posada can catch. If he can’t (but can still hit) then he can DH and let Matsui play the field. Nady’s in right, Damon’s in left, and they sign/trade for an underrated MLB-caliber outfielder to be in the rotation or start in left if Matsui DHs (short-term contract). Someone like Randy Winn who’s a league-average hitter and plus defender. Or Ryan Church.

This rotation is already really nice, assuming the Yankees actually sign some rotation depth for the guy who inevitably underperforms/gets injured. Sabathia or Burnett (who’s underrated) would just be icing on the cake.

Wang
Joba
Hughes
Moose/Pettitte
IPK/Rasner/the other Moose/Pettitte