What’s Going On in Tacoma?

marc w · May 24, 2011 at 11:45 pm · Filed Under Mariners 

Yesterday, someone on twitter asked what was going on with the Tacoma Rainiers’ starters’ ERA this year. The team ERA is nearly 5.40, over a full run worse than it was in 2010 – and that’s despite the fact that the 2011 figure doesn’t include the midsummer months. It’s not a BABIP thing: the picture’s largely the same using tRA or FIP. Obviously, the staff’s not exactly the same, and some of the guys who’ve pitched in both years look considerably worse from a scouting standpoint (Luke French, take a bow). The culprit’s pretty easy to identify: the staff’s hemorrhaging home runs.

In 2010, the Rainiers staff gave up 1 home run every 10.5 innings pitched. This year, it’s one per 7.6 IP. So far this year, teams have hit 63 home runs at the new Cheney Stadium through 22 games; that’s 2.9 HRs per game in Tacoma. Through 22 games in 2010, teams combined for 26 HRs, or 1.2 per game. One more crazy stat: through the first 22 games at Cheney in 2010, 9 were homerless. This year? None. Every game at new Cheney’s had at least one long ball.

Throughout its history, Cheney’s been one of the tougher PCL parks to hit homers in (check the park factors here or here). In 2011, it’s blowing the funhouse ballparks like Albuquerque out of the water: Despite video-game style HR factors (thanks in part to altitude), teams averaged 2.5 HR/game through 22 games last year in Albuquerque.

This isn’t about a dominant 2011 offense: the 2010 Rainiers led the league in home runs. It’s probably not about weather; you don’t need a baseball blog to tell you how cold and wet this spring’s been in the northwest. What’s changed since last year is the ballpark and the outfield walls. The OF dimensions haven’t changed at all, and the massive wall in CF (425 feet away) remains. The OF fences in left and right have been lowered, however. Rainiers announcer Mike Curto’s been keeping an unofficial tally of 2011 HRs that probably would’ve struck the wall in the old configuration, and he’s got 22 (probably 23 after today’s game). That is, a bit more than one ball per game has just cleared the new, lower walls at the new Cheney Stadium.

Personally, I just can’t see how lowering the fences would so radically change how the ballpark plays. My guess is that the new, much taller stadium has changed how wind moves through the outfield. That’s just a guess, but it makes more sense to me than the idea that teams would be battering the upper half of the walls in the old stadium. Seriously – if you cut the Safeco fence in half, or eliminated it entirely, would it have this kind of effect?

To be fair, the sample (22 games) is small, so this could just be coincidence. Given the weather, that’d be unlikely, but it’s not like Cheney’s never seen the wind blowing out before. It could also be the pitching staff. After yielding 7 HRs in 2010, French has already surrendered 15 in 2011. His velocity’s been down a bit too. Chaz Roe’s been awful in his first season with the club. Chris Seddon’s nearing his 2010 HR-allowed total already as well. The staff may not be great, but part of the reason they appear so bad is the spike in HR rate.

This highlights how difficult it can be to put minor league stats in their proper context. Omaha radically altered their ballpark this year too. Portland no longer exists, and Tucson’s back in the Pacific Coast League after the previous Tucson franchise moved to Reno a few years back. Multi-year factors help ameliorate year-to-year variance, but it’s tough when the league itself changes so much. Keep this in mind when you see Rainier pitcher RAs, or when you marvel at Mike Carp/Alex Liddi/Dustin Ackley’s home run totals.

Any other theories on what might be going on in Tacoma? Visiting hitters more comfortable now that their clubhouse is no longer a portable beyond the OF wall? Teams taking extra BP to stay warm on some frigid April nights?


4 Responses to “What’s Going On in Tacoma?”

  1. Paul B on May 25th, 2011 7:13 am

    I went to the Baseball America website and totalled up all the runs scored in Rainier games.

    Total runs per game (both teams):

    Home: 10.7
    Away: 12.8

    Based on that, I don’t think the issue is with Cheney.

  2. PositivePaul on May 25th, 2011 10:42 am

    Somehow, some way cERA is involved 😉

    Considering it’s not just an away-team-teeing-off-on-Rainiers-pitching thing, it HAS to be mostly ballpark factors. I’m sure some of it’s pitching quality (in the sense that there might be less overall pitching talent in AAA early on) but that increase in HRs is very noticeable and very dramatic…

  3. devzfan on May 25th, 2011 11:15 am


  4. nathaniel dawson on May 25th, 2011 5:44 pm

    The home run increase is dramatic when you look at home/road. I looked through the away games and counted the number of home runs, Tacoma pitchers at home have been giving up close to double the number of home runs as they’ve given up on the road, 1.55 HR’s per game at Cheney, .88 away. The hitters are much closer, but still knocking more over the Cheney fences than elsewhere. 1.27 at home, 1.08 on the road.

    That’s a pretty remarkable difference, but we’ve played less than 30 games in each split. I’d still go with it being a statistical anomaly unless we see that trend continue throughout the year. Definitely something worth keeping an eye on.

Leave a Reply

You must be logged in to post a comment.