6/11 Open Game Thread

James Paxton gets the ball for the Mariners tonight, and he's just about appointment viewing at this point. The big lefty cracked 100 miles per hour several times in his last outing against Cleveland, a game in which he struck out ten and was unlucky to allow the three runs he permitted. He also had a devastating slider and located all of his pitches better than usual.

Much of the credit for his strong outing was pinned on his lowered arm slot. For most of his professional career, Paxton has worked over the top, but he dropped to a low 3/4 slot recently, and he's continued throwing that way since rejoining the Mariners. At a glance, it seems like a pretty good example of cause and effect in action. Change the slot, throw strikes, hit 100, strike out seemingly every other hitter. Easy enough right?

I'm not entirely convinced. For one, it's not like Paxton was throwing slow before: throwing over the top, he hit the high-90's plenty of times in his first few years in Seattle. Second, it's not like a 3/4 arm angle is entirely new to him:

Paxton was also using the low slot in Tacoma early this year and he wasn't hitting anywhere near 100 then. Whatever phenomenon explains his velocity surge, it happened very recently, and it may not be entirely due to his arm slot.

Moreover, Paxton had plenty of success throwing over the top too. Coming into this season, Paxton had posted a 118 ERA+ and a 3.72 FIP in his first 30 big league starts. Those numbers perhaps understate how effectively he is capable of pitching with his old slot, marred as they are by the 13 outings he made last season while he was in, ah, less than peak physical condition.

Does this mean he should abandon the low slot? Not at all. He says he's throwing comfortably (HT Shannon Drayer) with that arm angle, and clearly it's conducive to helping him throw hard. It may even be the adjustment that helps him get over the hump and establish himself as a legitimate big league starter. Ultimately though, Paxton has always been simultaneously effective and wobbly. New slot or no, he's going to need to make a quite a few more starts like the outing he had on Monday to shake that reputation.