For some reason, the Rays have tried their hardest to keep Jeff Niemann in the dark…literally. One of the given reasons for slotting Wade Davis third in the rotation ahead of Niemann was because the spot had more scheduled day games in the early portion of the season. Faced with a day/night doubleheader today, Joe Maddon flipped Jeremy Hellickson to the afternoon when his “turn” in the rotation should have come after Niemann.
A quick check of the splits suggests that Niemann is a much better pitcher at night. In 17 day games, he has an ERA of 5.54 while allowing 14 home runs in 87.2 innings. In 53 evening contests, his ERA drops to 4.0. Meanwhile, his home runs per nine innings (K/9) falls to 1.0.
Call me a skeptic, but I find it hard to believe that Sunlight causes Niemann’s talent level to change. Given a larger sample size, his daytime statistics would likely regress toward his numbers in the night. In reality, he was fine in day games until last season.
Upon his return from the disabled list in late August, the right-hander made two daytime starts against the Los Angeles Angels. In those starts, he allowed 15 earned runs in a combined 7.2 innings. Since the entire sample size is only 17 games, two disastrous starts can skew the numbers. As a matter of fact, those two starts account for nearly 30% of his earned runs allowed in day games, meaning things probably seem worse than they actually are.
Nonetheless, the Rays’ front office and Joe Maddon are smart enough not to fall for such a selection bias. This leads me to believe there could be something beyond the numbers that affects Niemann before the sunsets. What that could be is anyone’s guess. Is it something as silly as Niemann being a late riser? Or is it something more technical like a tell in Niemann’s delivery or motion that is easier to detect in the daylight? Regardless of the reason, this is definitely one of the more unique “platoon” splits to consider.