The Mariners’ Spring Power and Traveling North

Sometimes it’s worth unpacking something that seems like it’s fairly cut and dry. Like, for example, the Mariners are showing quite a bit of power in spring training right now, but it seems like folly to put too much stock in those numbers. That statement alone can send you on a journey.

As of Thursday morning, the Seattle Mariners had hit 30 home runs this spring. The second-place team, the Cleveland Indians, had hit only 21. No other team had 20. In three times as many games last year, the Tigers led Spring Training with 46 home runs. Then again, the San Diego Padres led the National League last season so there’s clue number one that this power surge may not be such a big deal. (The Padres only hit more home runs than two teams in baseball last regular season).

But the Mariners tied for 14th in spring training home runs last year, and they’ve already hit more home runs than they did then. The new acquisitions must be working. Break up the Mariners.

Except that weather is a big part of power. And Arizona doesn’t have much in common with Seattle. Check out the average temperature by city last season:

There’s Arizona, all the way near the warmest part of the country, and Seattle over there by the coldest part of the country. Physics professor Robert Adair found that ten degrees of air temperature meant four extra feet of batted ball distance, so this means something. Jeff Zimmerman agreed, or he found that those same ten degrees meant 4.2 feet of distance. Our own site found a relationship between batted ball distance and home runs per fly ball, so this is meaningful stuff.

It’s not some ‘heavy air’ thing either. If you bucket games into temperatures as Zimmerman did, you find that the ball goes 274 feet in Seattle when it’s colder than 65 degrees, and 277 in the rest of the country at that temperature. When it’s over 65 degrees, the ball goes 279 feet in Seattle and 282 feet otherwise. The effect due to temperature is more stark than any effect due to humidity.

So it really looks like Arizona’s atmosphere is conducive to power and Seattle’s isn’t. But did you see Carson Cistulli post about spring training run environments and how there are *fewer* home runs in spring training then there are in the regular season? That’s weird.

Maybe it’s because it’s colder in Arizona in spring than your average mid-summer park? It’s 69 degrees there this year. That’s way colder than the seasonal average. It’s been 79 degrees the last two Marches in Phoenix, though. Either way, 69 is still warmer than Seattle, most days.

It can’t all be about weather. The studies looking at relationships between spring statistics and the regular season have found that component stats like strikeout and walk rates are more predictive than overall stats and in-season studies have found similar things about samples during the regular schedule. It takes a long time to know a player’s true-talent power level.

So if we were going to say something about the Mariners and their power this coming season, we’d have to first be able to say that the new parts will definitely show more power than the old parts. We do have, as ammunition, ZiPs projected isolated slugging numbers for next season, and a crude depth chart, too:

Looks like a few upgrades and a few downgrades and maybe a little nudge in the right direction. It’s no Slam Dunk Solution ™.

But then there’s John Dewan’s rule: in 2009, he showed in his Stat of the Week newsletter that players who beat their career slugging percentage by more than 200 points in Spring Training had more than a 60% chance at beating their career slugging percentage during the regular season (mininimum 200 regular season at-bats and 40 Spring Training at-bats). Does anyone satisfy his rule right now? Quite a few: Raul Ibanez, Franklin Gutierrez, Brendan Ryan, Justin Smoak, Jason Bay, Jesus Montero, Casper Wells and Michael Saunders.

Take out everyone definitively past their power peak — why would Jason Bay show a power surge beyond his career rates, at his age — and you get Justin Smoak, Michael Saunders and Jesus Montero. Those guys are maybe halfway to maybe showing something that could have a 60% likelihood of carrying over into the season.

At this point, things have gotten weird. The weather is some sort of factor, in a power-dampening way. The level of competition in spring training is a factor, also suggesting the team power surge is a mirage. The roster upheaval is a factor, and it seems like a positive, but the players doing the best this spring — doing so in the most believable way at least — were all on the team last year. It’s probably not the new guys. We’ll have to see about the fences.

It seems unlikely that this Mariner power surge will travel north. And we might have thought so from the beginning, but it was fun checking it out anyway. Maybe three young men and a set of new fences will make a grand impact against the odds.