Probably because Soler did outplay Heyward this year (at the plate), has a crapload of power that is kind of missing from this lineup outside of Bryzzo and Javy, had an .864 OPS since Aug 1st (not including 0-6 in the playoffs so far, too lazy to do the math) and had an OPS against lefties that was 230 points higher than Heywards in 2016. If you want to argue that its not worth benching Heyward against a lefty because of the drop off in defense, that's fine. But saying that he'll probably be just as bad at the plate as Heyward against a lefty is silly. check out their splits against the dodgers and at LA. Heyward has outhit him in both instances. Now, why exactly, idk, and sample size, but it seems to me that playing Heyward might make as much sense for his bat then his D. Looking past the fact that Soler has 7 career at bats in Dodger Stadium... how is this at all relevant?