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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.