The team announced at a news conference Thursday that Andreychuk will start his role on Oct. 1.
The Lightning had waived Andreychuk last January, saying the inspirational leader of their 2004 Stanley Cup championship team could not keep up with the speed the NHL's new rules have brought about.
"I never thought of myself being too far away from the game," Andreychuk said. "I'm excited to be back in the building, and to be able to watch hockey and contribute to this organization."
Andreychuk ranks second on the league's career list for left wingers in goals (640), assists (698) and points (1,338). He reached the 20-goal mark for the 19th time in 2003-04, third most in NHL history behind Gordie Howe (22) and Ron Francis (20). His 1,338 career points is tied for 23rd most in NHL history.
During the Lightning's playoff run in 2004, he had a goal and 13 assists on the way to being part of a Stanley Cup-winning team for the first time.
"I've had a great career," Andreychuk said. "Obviously, winning the Cup capped it off. I was, in no way, disappointed in what happened. So many positive things happened in my career. It's time to move on. It took a little while. I was ready for it."
Andreychuk has also played for Buffalo, Toronto, New Jersey, Boston and Colorado. He will be honoured in pre-game ceremonies before a game with the Sabres on Dec. 5.