A.J. Pollock Goes Hollywood by Mike Podhorzer January 28, 2019 On Saturday, A.J. Pollock signed a four-year deal with the Dodgers, after spending his entire career with the Diamondbacks. Before the introduction of the humidor last season, Chase Field (Diamondbacks) was one of the most hitter friendly parks in baseball. But the humidor changed that as intended. So now we have a real park factor battle between his old home and his new Dodger Stadium home. Since the FanGraphs 2018 park factors haven’t been published yet, I will share a comparison from another source. Unfortunately, this source is missing strikeout and walk factors, which could certainly have an effect. Park Factor Comparison TEAM 1b 2b 3b HR FB GB LD PU Runs Diamondbacks 100 95 152 97 99 100 100 94 100 Dodgers 99 104 70 102 99 101 97 103 95 SOURCE: Baseball Prospectus Obviously, health has been and remains the biggest question mark for Pollock. So let’s ignore the risk and focus solely on how the switch in home parks may affect his performance. The two parks are essentially neutral for singles, with Chase being exactly neutral and Dodger Stadium suppressing them by the most minor rate. On the other hand, Dodger Stadium is significantly more favorable for doubles, inflating them by 4%, while Chase actually suppressed them by 5%. Pollock has typically been a solid doubles hitter, though oddly his doubles rate plunged last year. Perhaps the largest park factor difference I have ever come across, Pollock is likely to lose a triple or two. Chase was the second best park for right-handed triples last year, while Dodger Stadium ranked second to last. With Pollock’s speed, he’s going to take a hit, but that still means just a triple or two, which isn’t going to make much of a dent in his overall results. Home runs is definitely one of the factors that took a hit by the humidor in Arizona. Suddenly the park is favorable for pitchers, leading to a boost for Pollock as he moves back into a park that slightly increases home runs. The thing is, Pollock is coming off the highest HR/FB rate of his career (which is ironic given how much more pitcher friendly his home park became), so it wouldn’t be the wisest to expect an even higher mark from last year. Basically, you would need to forecast what his mark would have been if he remained in Arizona, then factor in his new park. That likely puts him only marginally higher than pre-2018, depending on how much of his apparent power gains you think he could sustain. Moving on to batted ball type factors, Chase was more favorable for both line drives and pop-ups. Both metrics suggest that Pollock could take a minor hit in BABIP. After three straight seasons with a BABIP over .300, he hasn’t posted a mark exceeding .291 in the last two seasons. So while the park switch won’t help, he could very well rebound anyway given his history. Overall, despite the presence of the humidor, Chase ended up as a neutral park, which was still more hitter friendly than Dodger Stadium, which clearly favored pitchers. That said, it doesn’t automatically mean this is a bad move for Pollock, as fantasy owners care most about home runs, and the new park should be better. The Dodgers are also projected to score significantly more runs, which should boost his counting stats. The injury risk is always there, but I’m buying Pollock on any discount. This is an especially good move in a shallower league where you could find a reasonable replacement during Pollock’s inevitable time on the DL.