If you hang around Digital Domain Park when the Mets take off for road games, you get to enjoy the site of Johan Santana doing stuff. Specifically: throwing.

Santana, recovering from offseason shoulder surgery, is not throwing hard. From flat ground, he’ll take a hop-step and uncork an easy overhand. About 60 feet away, young righthander Tobi Stoner receives and fires it back.

So how did Stoner end up Santana’s throwing partner? He, too, is on a throwing program, building up strength in his arm after enduring some shoulder soreness following August surgery to clear out bone chips in his elbow.

Stoner plans to start working with the rest of the Mets’ pitchers soon, but said he will start the year in extended Spring Training as he continues to recover. As for Santana?

“He’s taking baby steps, but he’s making them,” Stoner said. “His mechanics are great. And even from 60 feet, he had a little more zip on his throws today.”

Stoner added that Santana, who had surgery to remove bone chips from his pitching elbow in both 2003 and 2009, has been giving him tips on developing consistency in his arm slot and release point.

“Not everyone gets to throw with Johan Santana so often,” said Stoner. “I’m trying to take it all in.”