I disagree with my friend Dave Cameron about Matt Adams being essentially helpless versus Bumgarner. There is no doubt that Bumgarner is a very good pitcher and is especially tough on lefty batters. Cameron claims that Adams is so poor against LHP, especially ones with large true splits like Bumgarner, that he is nearly an automatic out. While I agree that Adams versus Bumgarner is likely to end in a loud out at best, I don’t agree that Adams is practically worthless against lefty pitchers in general, and I don’t agree that a RH first baseman is a necessity for the Cardinals.
Cameron, to bolster his assertion, uses Adam’s actual stats versus LH pitchers this season, which are indeed awful. Even his career splits are bad. However, using actual platoon splits is not a good gauge for how a batter is going to do against LH and RH pitchers, especially for a player like Adams who barely has a couple of major league seasons under his belt. The sample sizes are just too small. He has only faced 193 LHP in his whole career. That is not nearly enough for that 51 wRC+ to have much meaning. Imagine using two months of a player’s stats to project his future performance – analysts would be screaming bloody murder! In addition, performance versus LHP informs performance against RHP and vice versa, notwithstanding a player’s unique platoon talent. In other words – and I know this sounds strange – but when projecting a player’s performance against same-handed opponents, we cannot ignore their performance against opposite-handed opponents, and vice versa. It’s still the same player.
Here’s how we need to project Adams against a LHP: We take his overall hitting projection, which is very good, a .336 wOBA according to Steamer projection system. Then we apply a projected platoon which is based on his actual platoon splits, regressed heavily toward the league average LHB. Once we do that, while we get a large projected platoon split, 41 points of wOBA (he is projected to hit 41 points better versus an average RHP than an average LHP), we get a hitting projection against lefties that is far above his actual stats against lefties. In fact, using the proper method for projecting a batter’s results versus LH and RH pitchers, we get a slightly below average hitter against LHP in Adams. Sure, versus a great pitcher like Bumgarner, his projected stats will be a lot less than that, but so will a RHB!
The moral of the story: Be very careful about using a player’s actual stats versus left and right-handed opponents as a stand-in for their projected platoon splits.
