There's going to be a lot of discussion about Jim Thome's potential value to the Twins in 2010 - how he can platoon with Delmon Young, rest Justin Morneau occasionally, be a presence in the clubhouse and provide a nice late-inning option for manager Ron Gardenhire. Just scroll down those blogs over there on the lower right, and you'll get plenty of solid analysis on all these aspects.
But I want to concentrate on just how valuable a bench bat is when used in late-inning situations? I've wondered about this since 2002 and 2003 when that role was often filled by Bobby Kielty. I remember writing about a quote from Ron Gardenhire stating that he thought Kielty was more valuable as a bench option than an everyday player, because that one 9th inning at-bat could be in a more valuable spot.
That's the kind of statement that makes disciples of advanced metrics like WAR throw up in their mouth a little bit. But it's also the kind of statement that makes disciples of advanced metrics like WPA applaud. Because it is undoubtedly true that a late inning at-bat can be much more valuable than an early inning at-bat. What isn't clear is how much more valuable, and whether it really makes sense to reserve a player for just those situations.
So with Thome joining the club, I crunched a few numbers for your digestion and comments. Let's start with a scenario. Imagine a player on the home team leading off an inning with a home run. How much does that home run really help the ball club?
The answer depends on the score and the inning. And you can see it in the graph below:
That axis at the bottom is innings. So if you look at the dark blue line (which represents when the home team trails by a run), it shows that if the home run leads off the first inning, it improves the teams chances to win by just over 10%. But if it happens in the ninth inning (where it ties the game), it improves the team's chance to win by over 45%. Think about that: the same hit, in the same situation but in a later inning, is four times more valuable in the ninth inning than in the first inning.
The temptation for people studying players is to write this finding off. After all, there's plenty of evidence that players aren't clutch. Thome can't choose to hit that home run late in the game as opposed to when it has less value. So from a player's perspective, when trying to determine their overall value, we focus on the raw numbers and not when it happened.
But we aren't really studying the player in this case - we're studying the manager. And the manager DOES get to make a choice. He gets to choose the best situation in which his bench players get to bat. Thome might not be more clutch in that position, but he's significantly more likely to hit a right-handed pitcher silly than Brendan Harris. If he hits a home run in that ninth inning of a one run game, it's more valuable than if he had hit a lead off home run in the first, third and fifth innings combined.
Of course, the chart also shows that it's significantly different if the game isn't a tie game or the home team isn't losing by just one run. If the home team is winning, putting that slugger in late innings to jack a ball into the right field bleachers doesn't add much, as the game is almost decided. That's fine - so keep in the defensive specialist. And if the home team is down by two runs, it's actually considerably more valuable to hit that lead off home run in the eighth inning than in the ninth, since it gives your team more time to come back.
So just how often do baseball games enter the ninth inning fairly close? Below you'll see some numbers for games between 1977 and 2006. I'm afraid I don't have percentages for you, but you can see close games are the most common occurrence, but not necessarily overwhelmingly so.
Finally, I should mention that I only charted the value increase of a specific outcome: a lead off home run. What if he struck out instead. I suspect that the difference isn't quite as pronounced with other outcomes, but the trend is similar. An out in the ninth inning of a one-run game is more important than an out in the second inning.
No matter what outcome you choose, in the late innings success counts more and failure hurts more. Either way, the manager wants to have a very good hitter available.
And now, he's got one.