You may have seen, heard, or noticed that the Mariners have an alarmingly enormous gap between their team ERA and FIP. 74 points, to be exact (4.84 vs. 4.10). They're tied with Cincinnati for the biggest difference in baseball, and Tampa Bay's the only other team that's even close.
Your immediate thought, then, is that they're due for a swift regression to the mean. That's how this usually works, right? The signs are there - the team LOB% (a measure of how often the pitching staff strands runners) stands at 67%, below the league average of 71%. This is presumably because, while their OPS against with nobody on base is .737 - 3% worse than the league average - their OPS against with runners in scoring position is .823, 15% worse than the league average. These are fluky numbers and such trends are unlikely to continue, which should help bring the ERA back down into an acceptable range.
Here's the problem, though - there are a pair of strong forces working against regression to the mean that aren't likely to go away. These are:
- Bad team defense
- Tons of luck on fly balls
The Hardball Times has the Mariner defense at -27 on groundballs and -13 on fly balls. What this means is that, based on the balls in play allowed by the pitching staff, the defense has turned 27 fewer grounders and 13 fewer fly balls into outs than expected. These two figures rank fifth-worst and seventh-worst overall, while the -40 defense as a whole is tied for third-worst in baseball. There is absolutely no arguing the fact that, despite stellar play by Ichiro and a big improvement by Jose Lopez, the Mariner team defense so far has been really, really bad. And a bad team defense will create a big gap between FIP and ERA, since FIP assumes that the pitching staff has a bunch of average gloves working the field. It's no coincidence that the Reds and D-Rays are the other teams with huge differences.
Is it going to get any better? The only prayer the Mariners have is that Betancourt figures out what he's doing wrong (and stops doing it), and that Adam Jones comes up and bumps Ibanez to DH. Were both of these to happen, then the defense going forward would probably be right around or a little above average - maybe even better than that, depending on Jones' adjustment. And that'd be great news for the pitching staff. The problem is that neither seem on the verge of taking place. Adam Jones needs to be with the big club playing LF for a multitude of reasons, but for a multitude of much stupider reasons, he isn't, and every day that he plays in Tacoma while Ibanez patrols the outfield is a day that we've neglected to make a massive upgrade and in so doing done damage to our playoff hopes. This team needs Adam Jones.
Anyway, team defense is only one of the points. The other is that, as difficult as it is to believe, this staff has been one of the luckiest on fly balls of any staff in the Majors. So far the pitchers as a whole have allowed 688 fly balls but only 46 home runs, for a staggeringly low 6.7% HR/FB rate. The league average, you remember, is ~11%, and the majority of pitchers have shown little to no ability to control this rate on a year-to-year basis.
Obviously, part of the issue is where the Mariners play half their games, but THT adjusts its numbers for park and the M's still come out with just an 8% HR/FB rate, still well below the average. This is pretty much an absolute certainty to get worse as the season wears on. Last year's Mariners, for example, allowed 183 home runs on 1709 fly balls for a much more reasonable (and not park-adjusted) 10.7% rate. There's no reason to expect the 2007 unit to keep getting so lucky. Were they allowing homers at last year's rate instead, their FIP would jump all the way up to their ERA, matching it almost exactly. And this is a regression that, I'm afraid, is unavoidable.
(The Mariners do get a bit of a break by playing in a division with average to crummy lineups, but the advantage isn't near big enough to explain this kind of good fortune. They're going to allow home runs.)
The Mariner pitching staff will look better over the rest of the season as it begins to strand more runners while undergoing some roster turnover, but the ERA regression won't be nearly as substantial as the team FIP would have you believe. Part of the issue will be more fly balls clearing the fence, and part will be a troubling defense, but regardless of the reason, the end result is this - the Mariners will continue to be a team that lives and dies by run production instead of run prevention. There's just no way that these pitchers and these defenders will allow the latter to become a strength.