[Syd Thrift]

OOTP players do indeed get rusty if you don't play them at least every few games or so. This has a small decrease in their effectiveness and also a small increase in their injury proneness. IME the single largest place you see this effect is the first games of spring training - those first 3-4 days are basically where you'll see the largest portion of injuries, major ones included, all season long.

But yeah... 2 weeks, a player will be less effective. The game won't necessarily tell you that they're rusty or what have you but they will be. It's also one good reason to put players who just got off the 60 day DL into a minor league rehab stint before calling them up: in the rehab stint they usually won't get used as hard as you might use them in the majors, and then if they do get hurt again you don't have to play around with your 25(6)/40 man rosters again. And you *do* see how much a guy's pitched over the last 5 days. I will generally try to make sure that everyone on my team who needs to be able to pitch in some kind of leveraged situation always has at least some non-zero number of pitches in that timeframe, even if it means using a setup guy for an inning at the end of a blowout loss.