Sinkerballers aren't immune to BABIP, but they can compenstate for it by allowing more negligible hits (grounders through the infied vs. linedrives off the outfield wall), allowing fewer homeruns, forcing double plays and issuing fewer runs. Marquis still has problems with walks, but he has been keeping the ball on the ground and inside the park. As long as he keeps that up, he'll be effective. If he doesn't, it will be 2006 all over again.