Watson, who was taking part in offseason conditioning program Thursday afternoon at Gillette Stadium, did not want to comment on the surgery he had in recent weeks, saying: "I can't talk about it," according to the paper.
Watson injured his ankle during the Patriots' Week 6 win at Dallas on Oct. 14 when he caught a pass and was tackled from behind by Cowboys safety Roy Williams.
After sitting out two games, Watson returned in Week 9 against Indianpolis. After aggravating the injury in the Pittsburgh game, he was inactive two of the last three regular-season games.
Watson might not be ready for training camp in July.
"It was defintiely an issue, but everyone has issues, stuff they fight through," he said, according to the Herald. "It was a nagging thing. Right now, it feels good."
Watson had 36 catches for 369 yards and six touchdowns last season.