Pablo López Joins the Twins

Last Friday, the Twins acquired starting pitcher Pablo López from the Marlins. After spending his entire career in Miami, how might his new park affect his performance? Let’s consult the park factors to find out.

Park Factor Comparison
Park (Team) 1B 2B 3B HR SO BB GB FB LD IFFB FIP Basic
LoanDepot Park (Marlins) 101 99 110 93 100 99 101 98 103 98 98 97
Target Field (Twins) 100 104 93 96 100 102 99 100 101 102 99 99

This is the type of comparison I prefer to dive into. It’s a nice mix of winners here, with neither park enjoying a clean sweep. Let’s dive in.

We’ll start with the non-home run hit type factors as usual. The singles factors are pretty darn close, with Target sitting neutral, while LoanDepot slightly inflates them. This factor has the biggest impact on BABIP. López has posted a .288 BABIP at home, versus a .295 mark on the road. That’s not a massive gap, but probably a bit wider than I’d expect based solely on the fact that LoanDepot inflates singles. Remember that players generally perform better at home, so you still might expect López to post a lower BABIP there.

Moving along to doubles, we find that Target is one of the better parks in baseball for hitting them, ranking in a tie for fifth most favorable park. This compares to LoanDepot, which slightly suppressed doubles last year. Given the higher doubles factor, López’s slugging percentage against could rise in his new park. Finally, we land on triples factors, which are dramatically different. This time, it’s Target that suppressed them , while LoanDepot was one of the better parks for them. López has only allowed 11 triples through his entire career, so while the park factor change is a positive, it’s going to barely make an impact.

Overall, the park switch is unlikely to have much of an impact on López’s BABIP, at least that you could tease out. But with a slightly lower singles factor, it’s a very slight positive move, reducing his forecast very marginally.

Now moving to home run factors, both parks suppressed them last year. I actually thought Target was home run friendly, but I guess not! LoanDepot was one of the most pitcher friendly home run parks in baseball last year, as it was tied for the third lowest HR park factor. López’s splits confirm how friendly his home park has been. He has posted just a 10.4% HR/FB rate at home, versus a 16.3% mark on the road. That’s a massive difference! He’s lucky he’s not going to one of the better home run parks in baseball, but his HR/FB rate forecast should still clearly increase due to the move.

The strikeout factors are identical, with both parks being neutral. However, Target increased walks last year, while LoanDepot suppressed them. López has posted near identical strikeout and walk rate splits in his career, but perhaps his walk rate forecast should increase slightly given the park factors.

Next up are the batted ball type factors. The ground ball and fly ball factors suggest López might post a slightly lower GB%, but higher FB%. In his career, he has posted a near identical GB% both home and away, but a higher FB% on the road. More important are the LD and IFFB factors. Both parks inflated line drives, but Target less so. López has posted a meaningfully higher LD% at home than on the road, so his LD% projection should be reduced in his less hitter friendly new park. Target also inflated infield fly balls, or pop-ups, which is another positive for BABIP. Amazingly, López has posted almost double the IFFB% on the road, versus at home. That’s crazy! The move to Target should certainly result in more easy outs.

These batted ball type factors play a big role in the hit type factors, so don’t make the mistake of double counting them. But it’s clear now that the singles factor is slightly better at Target because of the more pitcher friendly LD and IFFB factors compared to LoanDepot.

Finally we arrive at the summary factors, FIP and Basic, which is the five year run scoring factor. For each park, both factors indicates a run suppressing environment, but it’s less so at Target compared to LoanDepot. From the factors, it would appear that López’s BABIP might benefit ever so slightly, while his HR/FB rate should rise, which more than offsets the slight reduction in benefit. As a result, López’s ratio projections should increase due to the new home park.

Mike Podhorzer is the 2015 Fantasy Sports Writers Association Baseball Writer of the Year. He produces player projections using his own forecasting system and is the author of the eBook Projecting X 2.0: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. His projections helped him win the inaugural 2013 Tout Wars mixed draft league. Follow Mike on Twitter @MikePodhorzer and contact him via email.

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1 year ago

Great article, Mike. How are the Ks/BBs park factors calculated? What factors play into that to impact how a pitcher may perform in a given park?