If you're considering signing Tom Glavine to a multi-year, you'd want to have a pretty good idea of what Tom Glavine's going to do for those multi years.

Yet, the teams interested in Glavine -- especially the Phillies and Mets, both of which supposedly want Glavine for at least three years -- are likely just guessing about what Glavine's going to do for the next three seasons, during which he'll turn 37, 38 and 39.

	Tom Glavine Starting Pitcher Free agent Profile
	2002 SEASON STATISTICS GM W-L IP H SO ERA 36 18-11 224.1 210 127 2.96

But we don't have to guess. We can look at the history of good pitchers in their late 30s, and at least make an educated guess: a "hypothesis," if I remember my eighth-grade science correctly.

To that end, I employed Lee Sinins' profoundly useful Sabermetric Baseball Encyclopedia. Looking for a team- and ballpark-neutral statistic for measuring the effectiveness of pitchers, I turned to Sinins' "runs saved against average" (RSAA), which he describes as "the amount of runs that a pitcher saved vs. what an average pitcher would have allowed." You might quibble with the details, but it's a pretty straightforward concept, and certainly descriptive enough for our purposes.

Tom Glavine has saved 84 runs against average over the last three seasons, his Age 34 to Age 36 seasons (he was 36 on July 1 of the 2002 season). That's an excellent figure, tied with Ellis Kinder for 13th best in major-league history. It's nowhere near the best, though; the top four figures are held by Cy Young (174), Randy Johnson (148), Roger Clemens (116) and Greg Maddux (115). And no, it's probably not a coincidence that three of the top four spots are held by pitchers currently active (and yes, Cy Young was a superfreak).

Anyway, the point of this exercise is to find pitchers comparable to Glavine. I don't consider Glavine comparable to the aforementioned four hurlers, as they're all top-tier Hall of Famers who did substantially better in their mid-30s than Glavine did. I considered going with (at the upper end) pitchers with fewer than 100 RSAA over the three seasons, but the three in the 90s were Kevin Brown (99), Bob Gibson (91) and Curt Schilling (90). All of them power pitchers, all of them quite different than Tom Glavine.

So I wound up "boxing" the pitchers who compiled more 60 and fewer than 90 RSAA over the selected three seasons, and then I hacked a few guys off that list. Ellis Kinder (84 RSAA) got bumped because he became a reliever, Phil Niekro (81) and Hoyt Wilhelm (65) because they threw mostly knuckleballs, Walter Johnson (71) because Tom Glavine's no Walter Johnson, and Eddie Cicotte (65) because his Age 36 season was also his last season. Too, I eliminated Jim Bunning from the study because he pitched poorly at 36 (unlike Glavine), and Tommy Bridges because he didn't pitch during what would have been his Age 37 season (he returned a year later, but pitched just briefly).

And that left 14 pitchers: Red Ruffing (89), Steve Carlton (85), Preacher Roe (83), Gaylord Perry (76), David Cone (75), Jamie Moyer (72), Whitey Ford (71), Eddie Plank (70), Dolf Luque (64), Stan Coveleski (62), Warren Spahn (61), Waite Hoyt (61), Claude Passeau (61) and Tommy John (61). If there's a big problem with considering this group "representative," it's that Glavine sits near the top, in terms of both three-season performance and career value. Nevertheless, let's continue ...

Would you like to guess how many of those pitchers improved in their Age 37 seasons?

Zero.

Not one of the 14 pitchers -- remember, these are excellent pitchers, many of them in the Hall of Fame -- did better at 37 than 36.

That's surprising enough, I suppose. After all, we're talking about 14 outstanding pitchers, 14 outstanding pitchers who were not selected because they pitched particularly well when they were 36, but because they pitched particularly well from ages 34 through 36. We might expect at least a few of those pitchers to have performed particularly well at ages 34 and 35, then just so-so at 36 before bouncing back with a better season at 37.

It didn't happen, though.

Big deal, right? Probably just one of those things. But what's striking is just how precipitous was these pitchers' decline, as a group, at 37.

At 36, the 14 pitchers averaged 234 innings pitched, with 19.5 Runs Saved Above Average per 200 innings.

At 37, the 14 pitchers still averaged 189 innings ... but only 3.8 Runs Saved Above Average per 200 innings.

The best season among the Age 37 pitchers was posted by Tommy John, who pitched 265 innings and saved 16 runs above average; that is, he pitched roughly half as well as Tom Glavine did in 2002.

Mind you, that was the best season among the group.

Things do get better for the group at 38, however. Warren Spahn, Gaylord Perry, Steve Carlton, and Jamie Moyer all enjoyed nice comebacks, and Tommy John pitched even better, albeit in fewer innings.

Which is the bad news. Among the 14 pitchers, 10 pitched fewer innings at 38 than they'd pitched at 37. John actually has an excuse -- the strike in 1981 -- but most of them simply weren't as healthy at 38 as they'd been at 37. All 14 of the pitchers did see action at 38, but they averaged only 157 innings apiece, and five of them didn't manage 150 innings.

And as you might suspect, the trend continues at 39 and 40. Six of the 14 didn't pitch at all in their Age 39 seasons, and eight of them didn't pitch at 40. Of the six pitchers who did see action at 40, only Warren Spahn, Gaylord Perry and Eddie Plank pitched well.

What does it all mean?

Maybe it doesn't mean anything. Maybe Glavine is the new Gaylord Perry -- Perry's the only one of these guys who pitched well in each of the four seasons, 37 to 40 -- and he'll be the greatest investment since the Diamondbacks bought Randy Johnson. And maybe history is irrelevant because (for example) modern medicine and conditioning have made late-30s declines a thing of the past.

Maybe ... but probably not. And if I'm running a major-league team, I'd let somebody else conduct the experiment. Because the odds are pretty good that whoever signs Tom Glavine -- even if it's for "only" three years -- will be paying roughly $30 million for a couple of decent seasons.

So among Glavine's supposed suitors, it seems that only the Braves -- who have offered him a two-year contract, with a third year dependent on Glavine reaching certain levels of performance in the first two years -- have really thought this thing through. Because three guaranteed seasons is just asking for trouble.

Senior writer Rob Neyer, whose Big Book of Baseball Lineups will be published next spring by Fireside, will be appearing here regularly and irregularly during the offseason. His e-mail address is rob.neyer@dig.com.