Jon Lester and pitcher age curves

As of this writing, the teams with expressed interest in Jon Lester include the Cubs, Red Sox, Giants, Dodgers, Yankees and Braves, and it seems each day brings word of a new team. Whether this is true or merely a bargaining ploy by his agent to drive up his price and/or contract length remains to be seen. It could be bias from listening to Chicago sports radio station 670 The Score too much, but the Cubs appear to be the favorites to sign him.

The rumors are Lester will agree to a six-year deal in the neighborhood of $140 million. This Google Doc shows the aging curves for position players over the past fifty years or so, and in general the curve for pitchers follows similar patterns. Peak production for position players occurs around age 29 and gradually declines, with the level of decline commensurate with the ability of the player — the better the player, the slower the decline and the longer the career.

This chart shows fastball velocity by age for pitchers with at least 20 starts in a given season:

The bars are the number of pitchers with at least 20 starts since 2002 (left vertical axis) and the line shows the decrease in fastball velocity as pitchers age (right vertical axis). While the drop-off in the number of pitchers making 20+ starts in a year is fairly steep from ages 26-30, it flattens considerably after that. Conditional probability is at work — if a pitcher is a top-line pitcher at age 30, chances are he'll probably make it to 35 absent unforeseen circumstances. His production will likely diminish, and the rate of decrease will vary. This Google Docs spreadsheet shows the pitchers since 1960 with FanGraphs Wins Above Replacement (fWAR) seasons above 5.0 (i.e., All-Star caliber seasons), and it's not a short list.

Aggregate data is nice, but it's far more important to see what Lester has actually done. This Brooks Baseball chart shows the change in velocity in his pitches:

There is some decline in his fastball velocity, but it's not indicative of a big impending drop. In addition, he's throwing his fastball less and increasing his use of offspeed pitches, a natural progression most pitchers make as they age:

This change in pitch selection occurred last year, so it's too soon to definitively state it's due to aging, his short-term stint in Oakland, or other factors. If the move to more offspeed pitches is permanent, however, that's less strain he'll be putting on his arm.

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Lester (and Max Scherzer as well) don't really need to worry about aging curves — they've already proven their worth. Scherzer made a spectacular bet on himself last year when he turned down a contract rumored to be in the six-year/$140 million neighborhood, a move I freely admit I didn't understand at the time. Obviously, that bet will be paid off in his favor soon.

If I had a choice, I'd never sign a pitcher to longer than four years, and sell him on the idea that he can cash in again at a higher price in later years. The fact this never happens illustrates the market factors at play. It only takes one team to drive up either the price or contract length (or both), and any time the Yankees are mentioned, dollars and years can increase.

So is Jon Lester the profile of a pitcher worth $25 million over six, perhaps even seven years? If all the rumored teams are indeed serious, then chances are Lester will get six years, and $25 million seems to be the going rate for #1 starters not named Clayton Kershaw. The Cubs are reported to have an offer of six years/$138 million, or an average annual value of around $23 million — good work if you can get it.

There are no guarantees in baseball. Last year the Cubs offered Masahiro Tanaka a 6-year/$120 million contract, only to be outbid in dollars and years by the Yankees, and at the time I fully supported the attempt. Tanaka delivered everything he was supposed to do, until he went down with an injury in July. He came back to pitch in two games at the end of the season, but only time will tell if he fully recovers. Teams make educated decisions and hope they pay off, knowing that sometimes they won't. If the Cubs had signed Tanaka, they'd have five years and $100 million worth of question marks ahead of them going into 2015.

I see less risk in Jon Lester — he's had brief DL stints but nothing in the past two years. The Cubs have gone so far as to sign Ryan Dempster as a special assistant in charge of convincing Lester to sign with them. That's a very specific job description, and Dempster will earn every dollar if he accomplishes this. Lester turns 31 near the beginning of the season, and if he can deliver around 15-20 points of WAR he'll be worth his contract. Should he help Tom Ricketts, Theo Epstein, Jed Hoyer and the Cubs raise a World Series banner over Wrigley Field, the contract terms will be long-forgotten and irrelevant.

All data from FanGraphs. Charts from Brooks Baseball.

Scott Lindholm lives in Davenport, IA. Follow him on Twitter @ScottLindholm.