A mini-foofaraw stirred up after MLB 2K10 previews revealed the game had no check-swing mechanic. 2K Sports felt an improved batting eye and new "defensive swings" eliminated their need. But they've backtracked, and said check swings will be patched in.
So you'll now have four swings in MLB 2K10, all executed by the right analog stick. Pushing up is a normal swing. Pulling back and pushing up is a power swing. Pushing either right or left is the defensive swing they've introduced to help you foul off pitches, work the count, and tire out the pitcher or get the pitch you want to hit. Now there's the check swing, which is accomplished by drawing back on the right analog after you've executed one of the other three. Remember, check swing is just to keep from swinging at something outside the strike zone, a decision the batting eye and pitch tip is supposed to help you make before the ball arrives.
Frankly, I don't get it. Speaking strictly in terms of gameplay - I'm talking about the decisions you make for hitters you control - check swings as they are currently executed don't do much except offer cosmetic realism. Since swinging is mostly an instantaneous decision and you don't preload a swing, it's difficult to meaningfully install an "abort" command which is what a check-swing is. MLB 09 The Show does this by stopping the swing if you release the X button quickly mid-swing, but that can result in false positives. I can count on one hand the number of times I have successfully and intentionally checked my swing against a pitch thrown for a ball in MLB 09 The Show.
I've played MLB 2K10 on a pre-check swing build. The decision to swing is executed fast-twitch. I'll be interested to see how much delay they incorporate to allow you time enough to pull back and check a standard swing. And going back-up-back to check a power swing is just stupid. If you've committed to swing from your heels, you're probably going to follow through and if, in real life, you were to try to stop such an effort the bat would probably travel across the plate anyway. So, hooray, you get a called third strike instead of a swinging strikeout.