Rookie defensive lineman Sheldon Richardson missed another day of practice Thursday after undergoing root canal surgery Wednesday. Richardson said he is unsure when he will be cleared to practice. It depends on when the pain subsides. “It’s most definitely frustrating right now because I was progressing pretty good” the first-round pick from Missouri said. “I’m kind of mad I’m sitting out missing out on reps. I guess it happens.” Jets coach Rex Ryan said the coaches like what they’ve seen from Richardson so far. “We don’t want to put him in Canton yet but he looks pretty good” Ryan said. “He’s an explosive guy an explosive athlete. He certainly belongs here. He loves the game. You can tell. Just the way he plays he’s a very passionate guy.”