He was a ready-made ace right out of the package. A 1-1 MLB Draft pick from a prominent college baseball program with dominating numbers his junior season and the size and fastball velocity to match. For his first two MLB seasons, Paul Skenes delivered, too. His 1.96 ERA in over 300 innings those two years was the best two-year start to a career since they lowered the mound in 1969, better than Dwight Gooden and Blake Snell and Vida Blue and Orel Hershiser.This year, it’s been a different story. Through Wednesday, Skenes had the 51st-best ERA among the 96 pitchers who have thrown 100 innings. For the first time in his career, he’s had to brush off questions about why he’s struggling.There’s one obvious thing wrong, and it’s the first metric people check in this modern era of pitching. Skenes’ velocity is down. After sitting over 98 mph with his four-seamer in his first two seasons, he’s dropped all the way down to 96.4 over the last month. The whittling away of his velocity seems to chart pretty well against his ballooning ERA.While it may seem like the obvious answer, Skenes himself is not convinced that declining velocity is the issue.“I don’t think velocity is something I need to pitch well,” Skenes said on media day at the All-Star Game. “I think it’s probably the first time in my career the velo has kinda dipped. It’s not something that I’m stressed over at all. I’m healthy. I’m feeling good and still pitching at a high level.”But following his last outing, during which his velocity dipped under 96 mph for the first time and he left after throwing just 65 pitches, he seemed to have a slightly different take on it."I think I've probably had more 30- to 35-pitch innings this year than I have probably in the last two years combined, so that doesn't help either," he said after that start. "It's still volume, even if it doesn't show up on the innings total. That's probably part of it, too."If the velocity drop is due to workload, it seems like rest would be the only balm. There could be some mechanical issues, too. One pitching coach mentioned in a story on MLB.com that he looked a little more "cross-body" this year. In the two photos below, look at how his legs lined up upon release last year (left) and how they are this year (right) and there's some evidence of Skenes throwing against his body more this year. That cross-body move would rob him of some power toward the plate.But even at 96 mph, Skenes has pretty good velocity — that would be top quartile in the league, on par with other great pitchers such as Yoshinobu Yamamoto and Chris Sale. Couldn't he still have great success at this level at 96 mph, as he suggests?Perhaps, but there were some concerns about his pitch shapes coming out of college, and those concerns have been exacerbated during his struggles, too. This year, his four-seam fastball has lost a little horizontal movement, gained a little vertical movement and his arm slot has raised a little. All those little changes mean that his four-seam movement is closer to "dead zone" than it's ever been. A dead zone fastball has movement that's completely predicted by a pitcher's arm slot, and he's now just an inch away from such a fastball, vertically speaking.