Low Power Bats in New Digs

Erik Manning did a fine job looking at the Scott Rolen-to-Cincinnati trade from a transactional standpoint, but fantasy managers might be interested in the prognosis for Rolen’s power in his new address. The same could be said of fantasy managers looking at Nick Johnson in Florida.

At first glance, Rolen should enjoy playing in Great American Ball Park. Though park factors aren’t always consistent from year to year, the Reds ballpark is consistently favorable to hitters. It has a 1.063 park factor for home runs this year, but last year that number was 1.23 and in 2007 it was the second-best park for power (with a whopping 1.351 park factor. In the three years before this year, the park consistently awarded over 20% more home runs than a neutral ballpark.

ZiPS RoS has Rolen down for a whopping four more home runs, though. 20% more than four is not very exciting. Is it possible that Rolen will see a more significant boost in power? His home runs per fly ball have been pretty stable for the past three years, hovering around 7%. His fly ball percentage has also been stable (around 40%), though lower than it was when he was more of a power hitter. In fact, his current 41.9% fly ball percentage and 6.3% home run per fly ball are his worst and second-worst marks in those respective categories.

The power is not coming back. Judging from the comments on R.J. Anderson’s recent article on Rolen it seems the power outage is part of a concerted effort to revamp his swing after his shoulder woes. At least his line drive gains seem for real (two straight years of improvement, and his current 25.2% would only be his second-best mark ever), and that park can help boost all his non-home run hits as well. He still gets a little boost with the move.

Nick Johnson’s move is in the wrong direction. He’s already currently sporting a slugging percentage below his on-base percentage, which is not an easy thing to do, and he’s moving from a neutral-to-offensive park to a known pitcher’s park in Florida.

At least, it used to be a pitcher’s park. “Land Shark” stadium is currently sporting a robust 1.182 park factor for home runs, ranking fourth in that category in the league, and 23 spots above Nationals Park and its .791 number. Is Johnson in line for a 30% power boost? Not so fast. The average park factor in Florida, from 2006-2008, was .91. Nationals park last year played to a .942 park factor for home runs over the full year.

Rolen is moving from an offense that ranks tenth in the league in runs to one that ranks 26th, so he’ll feel a hit in the runs and RBI categories that could undo any positive park effects. Johnson is moving from a team that ranks 20th in runs to one that ranks 17th and has negligible park effect differences. The unexciting conclusion is that these low-power bats will not gain much in their new homes.




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Graphs: Baseball, Roto, Beer, brats (OK, no graphs for that...yet), repeat. Follow him on Twitter @enosarris.


7 Responses to “Low Power Bats in New Digs”

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  1. alskor says:

    Casey Kotchman in Boston. Won’t play much but I think his power will be very much helped there.

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    • Joe R says:

      Actually, Fenway’s been traditionally very hard to hit home runs in, surprisingly. Outside of hooking one right down the RF line, Fenway ranges from average to hard.

      For all I know Kotchman may hit a few flukes down the line, but I wouldn’t exactly bet the farm on it.

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  2. Derek Carty says:

    Eno, wouldn’t we need to consider the park Rolen is coming from? Those ZiPS projections are, I imagine, based upon Rolen in the Rogers Centre. Moving him into Great American wouldn’t be the same as him coming from a neutral park, so we couldn’t just apply the Great American corrections. In all actuality, his power will probably drop by a small amount since the Rogers Centre is more favorable to HR hitters (in general) than Great American.

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    • joser says:

      There are more HRs hit per game at Rogers Center than at Great American, but that also reflects the teams that play there.

      Looking at the Hit Tracker data for Rolen going back through 2006, he has hit 49 home runs in various parks: 10 to LF, 29 to LCF, 9 to CF, and 1 to RCF. He’s a pull right hand hitter (at least as far as HRs are concerned), and this year all of his HRs were to LCF except for a couple to LF. According to the Home Run Park Factor calculations Rybarczyk published at THT in 2007, Great American Ball Park is about the same as Rogers Center down the left field line but is considerably more hitter-friendly in left center (which matters most for Rolen) and right center, and is slightly more hitter-friendly (or slightly less hitter-unfriendly) in dead CF as well.

      Given this, I would expect Rolen’s full-season HR totals to rise from the switch in home parks, all other things being equal. (Of course, with age and injuries coming into play, they aren’t necessarily).

      I don’t think I can include link tags that lead off Fangraphs, so:

      Hit tracker: http://www.hittrackeronline.com/index.php?sortm=hitter&sort=asc&skip=2400
      (note that horizontal angle is calculated counter-clockwise, so that 63 degrees is RCF and 118 degrees is LCF, with 45 and 135 being the right and left foul poles)

      THT park factors: http://www.hardballtimes.com/main/article/home-run-park-factor-a-new-approach/

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  3. Eno Sarris says:

    Pardon me if my understanding of hittrackeronline.com is incorrect, but it’s not the easiest site to navigate: is there a place on that website to find data about non-home runs? Maybe with hit f/x we’ll see more of that.

    Does someone have a good site for hit spray charts so we can do more of the work like joser’s work here? We could be more precise that way. But joser’s line of reasoning seems pretty good – thanks for posting.

    We are probably splitting hairs in the end. Don’t know how much a park can do for a guy with the basic underlying power Rolen is showing right now.

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  4. Walker says:

    I have a question on park factors, because to me they don’t make sense. You say Great American Ballpark is more of a pitchers park this year and that park factors vary from year to year, doesn’t that depend on the makeup of the team they have and the quality of hitters versus pitchers.

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    • Derek Carty says:

      Walker,
      Park factors are independent of the teams that play there. Simply, they’re calculated by looking at how those who play in the park fare both in the park and in other parks and comparing the two.

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