CLEARWATER, Fla. — Roy Halladay is back wearing a Philadelphia Phillies uniform.

The two-time Cy Young Award winner returned Tuesday to serve as a guest instructor in spring training. Halladay, who threw a perfect game in his first season in Philadelphia in 2010 and a no-hitter later that year in his first post-season start, is considering a more permanent role in the big leagues.

"I definitely want to get back in," Halladay said. "So just getting here and being around, obviously with a new front office they need to see who you are. I think it’s just a great opportunity to get out here again and be around the guys. Especially with so many new, young players, it’s exciting for a guy like myself to come in and watch them. If I can share anything that’ll help them, that’s awesome."

The 39-year-old Halladay plans to work with pitchers on the mental side of the game along with the fundamentals and mechanics of pitching.

"Whatever concerns they may have, if any, or talking about things that helped me be successful, so it can cover a range of things," Halladay said. "For me, it’s just a pleasure to be able to help out. If it’s throwing BP, I’ll throw BP."

Halladay watched young starters Zach Eflin and Jake Thompson throw and talked with others on his first day in camp.

"He’s probably 95 per cent mental whether it’s thought process going into pitches or sequence, it’s incredible," Thompson said.

Eflin said he was excited to introduce himself to Halladay.

Halladay spent 16 seasons in the major leagues with the Toronto Blue Jays and Phillies. He retired in December 2013 because of an ailing back. Halladay was a guest instructor with the Phillies in 2014 but hadn’t returned until now.

"There are all kinds of options," he said about his future in baseball. "I don’t ever try to get too far ahead of myself. I’m going to enjoy this first week here, being a guest coach, and see where things go. We’ll continue talking, but, you know, I think it’s always trying to find a good fit, too."

Halladay was 203-105 with a 3.38 ERA in 416 career games, including 390 starts. He had 67 complete games and 20 shutouts. His resume includes three 20-win seasons, eight All-Star games, and three other top-3 finishes for the Cy Young Award.

He’s going to Cooperstown this summer with one of his son’s baseball teams and looks forward to possibly being enshrined in the Hall of Fame one day.

"You see guys get in that are deserving and you see guys that are possibly deserving that don’t get in," he said. "Boy, it’s a tough thing to figure out. But absolutely I would love to be there. I think every player who ever played the game would love to be there. It would be a tremendous honour."