clock menu more-arrow no yes mobile

Filed under:

One more Joba article - comparing him to Pettitte

I'm going back to the previous Joba article I wrote, in which I compared him to Andy Pettitte over the last two years. I was curious about how Joba's shorter starts compared to Pettitte's higher ERA.

Joba's ERA as a starter is 3.62; Pettitte's, over the same period, is 4.65. Joba has averaged 5.1 innings per start; Pettitte a hair over six. Joba has thrown 154.1 innings as a starter; Pettitte has tossed 311.2 in the same period.

Using RAR (Runs Above Replacement), which combines innings with quality (ERA) to determine how many runs a pitcher has saved (beyond that of a replacement-level pitcher), I looked at the pitchers in question.

Despite Andy's two-to-one advantage in innings pitched (311.2 vs. 154.1), he's still only saved one more run than Joba: 35.7 vs. 34.7. Then when you divide by number of starts (to find out who's better on a per-game basis), Joba comes out on top by almost double - he's worth 1.2 RAR per-start compared to Pettitte's .7 RAR per-start.

I also looked at RAR using tRA (Total Run Average), which the experts say is a more accurate way of measuring a pitcher (because it counts unearned runs along with earned runs). Joba has allowed more unearned runs than Pettitte, and does not come as close to matching his total RAR (30.1 vs. 45.5), but is still better on a per-game basis: 1.04 RAR/start vs. Pettitte's .89 RAR/start.

To conclude: as bad as Joba has been recently, Pettitte has been worse. And it's not fair to condemn Joba to the bullpen when there's another pitcher in the same rotation more deserving of that demotion. The simple fact is that, over the last 1.5 years, Joba has been a better starter than Andy Pettitte. Joba is not the one deserving of any demotion.

Hopefully Joba pitches great on Sunday and we don't have to discuss this for a while (and by 'a while,' I mean a week).

Thank god baseball's back tonight.


(Thanks to BTB's Sky Kalkman for the RAR formula: repERA-pitcherERA, * IP, / 9 = RAR (where repERA = lgERA * 1.28))

It's a great formula to play around with. For example, to match CC Sabathia's season so far (128.1 ip, 3.86 ERA), a reliever, pitching 40 innings (the Yankee reliever average), would need a .25 ERA. That's a good example of how much more valuable starting is than relieving.

If anyone's interested, the Excel document is here.

[Disclaimer: my intention is not to denigrate Andy Pettitte, but to defend Joba Chamberlain. For the record, I don't think either pitcher should be in the bullpen at this point.]