Stephen Pryor (lat) threw his fourth bullpen session of the spring on Tuesday in Mariners camp. Pryor is making slow but steady progress in his recovery from major lat surgery. "We're going very slow and deliberate and that's on purpose," said manager Lloyd McClendon. "We're not going to rush this young man. He's throwing good, he feels good. But we need to get that velocity up where it needs to be for him to be the dominant guy we know he can be. You just can't rush the process." Pryor is expected to miss the first few months of the 2014 regular season.