Pop quiz, hot shot: If the Houston Astros hit 108 home runs last season and had one of the worst offenses in the National League, how many will they need to hit to become league average?
Much like Dennis Hopper, there is no right answer to my question, partly because home runs aren't the end-all, be-all of offensive production. They certainly help, but so does a higher on-base percentage. Still, after looking at the numbers on Tuesday, I thought it'd be interesting to see just how many home runs the Astros can expect to hit this season and if it'll approach the league average of 150 from last season.
So, let's take the projected lineup and add up how many home runs they hit last season:
1) Michael Bourn -2
2) Clint Barmes -8
3) Hunter Pence -25
4) Carlos Lee -24
5) Chris Johnson -11
6) Bill Hall -18
7) Brett Wallace -2
8) Jason Castro -2
Add in two or three from the pitchers and maybe five or six from the bench, and that brings us to 101 home runs next season. But, wait! That's not very sabermetric of you, David. After all, we didn't control for plate appearances, as Johnson, Wallace and Castro only played part time. So, what if we used home run rates and multiplied that by 600 plate appearances?
That number would be 128, counting 10 or so from non-starters. Still, we're lacking some more refinement to this prediction game. After the jump, let's look at two slightly more sophisticated ways to make this guess.
While looking at home run rates does get us closer to the objective, we're still not 100 percent there. For instance, we don't know how the two transplants will hit at Minute Maid Park. Here are Bill Hall and Clint Barmes' career stats in Houston:
Hall -1 career HR in 164 plate appearances
Barmes - 1 career HR in 55 plate appearances
Neither of those stats are terribly convincing, especially since our rate stats have Hall hitting 28 home runs in 2011. So, let's downgrade Hall somewhat on his rate, using his three-year average HR rate instead of just last year. That gives him 21 home runs next season. But, he's also hit 56 percent of his career home runs at home, and we don't know what to expect with him at MMP. So, let's cut that number down a bit and what are we left with? About 18 home runs, or what he hit in 2010.
As for Barmes, we'll do the same thing. His three-year rate puts him at 17 home runs next season. But, if we discount for his excellent home ballpark numbers, we're left with a slightly lower number. 25 of his 42 home runs over the past three seasons have come at home. Let's cut his home total in half, giving him 12 home runs next season.
We're still missing something here. Both of these guys played in weird situations in 2010. Hall played in the American League East, one of the toughest divisions in baseball. Moving to the National League, will we see his production tick up a notch? Will playing every day also help that? Let's say he'll average 25 plate appearances at parks in the NL Central. With his career HR rate in each of those parks, he should hit five road home runs against those teams next season. Add in another five in his other 45 road games and we're already at 10 home runs. If we're assuming he'll hit about 11 at MMP, adding in a bump for league performance, we could bump Hall back up to about 22 homers next season.
Barmes, similarly, played in a great hitter's park in 2010, but he also played in some really tough pitcher's parks in division. Moving to the NL Central may help him some on the road (at least, that's a solid theory). Looking at his career HR rates for NL Central parks, Barmes should hit somewhere around two home runs in 36 or so in-division games. I don't think we can plan on him hitting more than two in his other road games, which leaves him at four total away from MMP. In that scenario, Barmes may struggle to hit 12 home runs next season.
So, we've got 34 home runs from the two newbies. What can we learn from our other lineup additions?
Carlos Lee is probably a pretty safe bet to hit another 25 home runs. He might bounce back some and he might regress, so let's just leave him smack dab in the middle of those two predictions. Hunter Pence is also remarkably consistent and we can probably pencil him in for another 25. Michael Bourn is consistent in another way, so we shouldn't count on more than one or two from him. That leaves our trio of young guys in Wallace, Castro and Johnson left to figure out, with 86 home runs already accounted for.
Johnson is one of the hardest players to figure out. Yes, his numbers were fueled by a high BABiP. But, as I pointed out here, the way he got his hits may lead to only a slight drop in his numbers. Johnson was also shut out of hitting home runs in Cincinnati, St. Louis and Milwaukee last season, but still hit four in-division road games last season. So, if we assume he'll average at least one in those three cities, plus three more for the last two, he'd have six home runs in NL Central road games. Add in another four in his other road games, plus 11 at home, and Johnson sits at 21 for the season. Lowering things for a slight regression, let's give him 19 home runs, which puts us at 105 with just Castro and Wallace left.
With Castro, we don't have a good handle on how much power he might have. I averaged together his home run rates from Corpus Christ in 2009, Round Rock in 2010 and Houston in 2010 to see what he might be capable of. That puts him at 7 HR next season, which is a fairly reasonable number.
Wallace, on the other hand, is a big ole enigma. I'm inclined to think he's got the potential to hit 15-20 home runs next season, but that'd be showing much more power than he did last season. It's not out of the question, though, since he did flash some power in the minors (albeit in hitter friendly parks). So, let's downgrade him from my optimistic total to 13 home runs (which is still optimistic), and assume he wins the job and stays in the majors for 600 plate appearances.
That leaves us with 125 home runs from our regulars. Add in another 10 and we're left with 135, which is still lower than the league average by about 15 home runs, but is a bit of an improvement over last season.
Just out of curiosity, here's what Bill James, Marcel and the Fans at FanGraphs have to say about each player's totals:
1) Michael Bourn - 4, 4, 2
2) Clint Barmes -12, 13
3) Hunter Pence -26, 21, 25
4) Carlos Lee -27, 22, 22
5) Chris Johnson -18, 11, 15
6) Bill Hall -21, 14
7) Brett Wallace -0*, 6, 16
8) Jason Castro -5, 6
*James didn't project Wallace for 2011
So Bill James has the Astros regulars at 113, Marcel at 96 and the fans at 113. Add in 10 for the bench and pitchers and Marcel is the only system that doesn't project the Astros to have more home runs than last season. Which is a positive sign, I guess. None of these systems were as optimistic as my guesses, but they're all around the same numbers.
What do you think? Are there any glaring omissions here? Any numbers you think should be higher? Any changes you'd make? What will an extra 20-30 home runs do for the Astros offense next season?