Yeah, with these small sample sizes, I'd guess I'd defer to the staff as to who can do what. I didn't see the Easter Sunday game, but that Martin went to center today probably means the staff trusts him in center no matter what happened that day. Margot has been unimpressive so far, but he's been a pretty good player for seven years.
I don't agree with every evaluation and managerial decision, but Baldelli and the coaching staff see them a lot more than any of us do.
I do think "the poorly constructed roster" could be fixed by trust in one more lefty bat. Yeah, Kirilloff's not going to hit .400, but if only two guys are platooned, there's an extra guy for a late-inning move, be it a pinch runner or pinch hitting or defensive replacement.