Is John Smoltz having a good year?

That may seem like a ridiculous question. After all, Smoltz is mounting a serious challenge to the single-season saves record, piling up 39 saves through 108 games. That's a pace for 59 saves by season's end, two more than Bobby Thigpen's 12-year-old standard. The saves alone make Smoltz's year a great one, right?

In a word, no. Saves get lots of attention, but they're as much a function of opportunity as performance. Antonio Alfonseca piled up 45 saves in 2000, but nobody thinks of that season when they think of all-time great relief years, largely because of his mediocre ERA of 4.24. When your teammates and your manager create 49 save opportunities for you, as the Marlins did that year for Alfonseca, even so-so pitching will result in a gaudy save total. That general story has been repeated quite often during the closer era: Jeff Reardon in 1985, Lee Smith in 1992 and 1993, Mitch Williams in 1993, Armando Benitez last year, and many others.

Now along comes Smoltz, who's putting up his big save numbers with an ERA almost as high as Alfonseca's was two years ago. Smoltz's ERA through Thursday stands at 3.90, only a little better than the NL average of 4.11, and only the seventh-best ERA in the Braves bullpen. Forget the MVP buzz Smoltz is getting -- does this even count as a good year for him?

Well, yes. Smoltz is having a fine year, much better than his 3.90 ERA would suggest. While ERA is a much better stat for measuring pitcher performance than saves are, it can also be misleading, especially for relievers. A big part of a reliever's job is situational, and that aspect is completely missed by ERA. ERA has two basic problems when it comes to measuring run prevention by relievers: it doesn't measure how the relievers handle inherited runners when it should, and it does measure how the reliever's successors handle his inherited runners when it shouldn't.

For many relievers, these situational factors even out, leaving ERA as a pretty good measure of their contribution. But every year there are some relievers whose contributions don't show up well in the box score numbers, and this year Smoltz is one of them. At Baseball Prospectus, we run a Reliever Report that tracks a few statistics designed to handle the situational aspects of relief pitching better than ERA does. Those numbers show that Smoltz's 3.90 ERA is understating his performance by a fair bit.

Here are four reasons Smoltz is better than his ERA:

1. He hasn't given up any unearned runs. I could go into a long diatribe here about the silliness of the unearned-run rule, but I won't. Suffice it to say that I think Smoltz's unearned run total of zero has at least as much to do with his pitching as it does the Braves fielding. While Smoltz's ERA of 3.90 isn't that different from the NL ERA of 4.11, Smoltz's RA (without the "E") of 3.90 is more than half a run better than the NL RA of 4.49. This may seem like a small thing, but when we're talking about a pitcher who's given up just 25 runs all year, these small things add up quickly.

2. He's done a great job stranding inherited runners. Smoltz has inherited 13 runners so far this season. From where those runners were on base and how many outs there were when Smoltz took over, you'd expect those 13 runners to score 6.1 runs on average. Smoltz allowed just two of them to score, and none of the others were left on base when Smoltz left the game, meaning Smoltz saved his staff-mates around four runs. That makes him ninth-best in the majors this year at handling inherited runners.

3. He's gotten no help when he's turned over his own runners. As a closer, Smoltz doesn't leave the game with runners on base very often. In fact, he's only done it in one game this year, but that one game was a disaster. (More about that below.) He left the game with the bases loaded and two outs. On average in that situation, Smoltz's three runners would be expected to score only 0.6 runs. However, Smoltz's teammate Aaron Small surrendered a bases-clearing double -- to Rey Ordonez of all people -- costing Smoltz more than two runs over what you'd expect from average pitching. That one game is enough to rank Smoltz 10th from the bottom in the majors in receiving help from his relievers.

You can put together reasons 2 and 3 to get a sense of how well the conventional run prevention stats -- like ERA -- are over- or underestimating the reliever's contribution. Doing that for this year shows Smoltz as the third most underrated reliever in the majors so far, behind only Jim Mecir of the A's and Scott Sullivan of the Reds.

4. One bad game is having a disproportionate impact on his ERA. Braves fans would like to forget the April 6 Mets/Braves matchup, in which Smoltz was brought in to preserve a 2-2 tie in the ninth and ended up being charged with eight earned runs. Those eight runs represent almost a third of the runs Smoltz has given up this year, but most of them just didn't make that much difference in that game. The game was pretty much lost after the Mets had scored two runs, and it was definitely lost after the Mets had scored four runs, but Bobby Cox left Smoltz in to face more batters and give up a few more meaningless runs.

I'm not here to overstate the case for Smoltz. He's not the most valuable reliever in the majors this year. He may not even be the most valuable reliever on his own team. The MVP buzz surrounding him is ridiculous. At the same time, this is not just another Alfonseca season. Smoltz has spent most of the year recovering from one bad game and doing the things that don't show up in the box score. He's having a fine season despite the ERA. With a deep bullpen anchored by Smoltz, the Braves should be in terrific shape come October.

You can check out more work from the team of writers of the Baseball Prospectus (tm) at their web site at baseballprospectus.com. Michael Wolverton can be reached at mjw@baseballprospectus.com.