Manuel Margot, CF
Margot came into his first taste of full-season ball with a bang, but he's had a rough May, batting just .185/.279/.278 this month. He's not striking out overly much, with just nine punch outs in 61 May plate appearances (15 percent), but the power he displayed in April has been missing, and he can't seem to get the singles to fall in. The fact he's not punching out a ton, and that he's still walking, is a positive, though, especially when you remember he's all of 19 years old.
It's probably a small sample oddity, but he's been much better against his fellow right-handers to start the season than against southpaws. You'd expect him to hit lefties well considering he's a righty, so maybe as that line corrects itself, Margot's season will look more like what you hope it would.
Jamie Callahan, RHP
At this point, I'm just going to keep repeating in my head that Jamie Callahan is only 19 years old every time I look at his numbers. The strikeouts are encouraging, the walks disappointing but not disheartening given his youth and inexperience, but that hit rate. Part of it might be the fact he's pitching on front of a Low-A defense, but at over 12 per nine innings, most of it is likely a command thing: Callahan isn't putting the ball where he needs to in order to give himself the best chance at an out. This is one of those moments where failure can be a great lesson for Callahan.
Myles Smith, RHP
The same can be said for Myles Smith, who has also had an even rougher May than April. He doesn't have the youth of Callahan, but he's a relatively new convert to full-time pitching, so the inexperience portion of the equation still matters for him, even if it's just Low-A.
Unlike Callahan, Smith is walking more batters than he's striking out, is giving up a homer per nine, and has the lofty hit rate on top of all of that. He's been a total mess against both left-handed and right-handed opponents, as well as with runners on base. It's a very small sample given it's only mid-May and we're breaking it down even further, but he's been much better with the bases empty. It's probably not the source of all of his problems, but Smith might be having significant problems from the stretch in terms of locating his pitches. It's, at the least, something worth keeping an eye on.