After a stop-and-start beginning to spring training for Johan Santana, the Mets have told the lefty to proceed slowly and with caution. With that in mind, Santana is not likely to make his Grapefruit League debut Thursday, as had been expected, and his status as the Opening Day starter is even more doubtful.

“Right now, it’s day to day with Johan,” Terry Collins said Saturday. “We would certainly hope next week (for his spring training debut). If it’s not, it’s not. Again, he’s going to be ready when he’s ready.”

After a throwing session Friday, Santana did not participate in the team’s stretching and workouts Saturday morning. Instead, Collins said the 33-year-old did his own arm stretching and flexibility work on his surgically repaired shoulder.

Collins emphasized that Santana felt no discomfort in the shoulder, but said there may be some fatigue because of the aggressive schedule the pitcher had been pursuing to get into a game.

“Last week, because of his displeasure for what was going on, what was being said, he sort of rushed things, so I said we are going to go back to the pace we feel comfortable with,” Collins said