Titans coach Mike Munchak says he doesn’t know if quarterback Matt Hasselbeck will be healthy enough to start this Sunday’s game against winless Indianapolis.The bigger question is does it matter?Rookie QB Jake Locker showed last Sunday against the Saints the rocket arm and quick feet that made him the Titans first-round draft pick. The promising outlook for the Titans is Locker is just one of five rookies who have made a definite impact as Tennessee battles for a wildcard playoff berth.While Locker may be the gem of the rookie class, the Titans drafted four playmakers on the defensive side of the ball.Outside linebacker Akeem Ayers has been a solid contributor all season with 60 tackles and two sacks. Middle linebacker Colin McCarthy has been a spark since replacing injured Barrett Ruud.