The 27-year-old scored 30 goals in 123 appearances for the Hatters since signing from Barnsley in the summer of 2017.
The West Ham United academy graduate has struggled for regular game time since Luton won promotion from League One in 2018/19, spending the last campaign and a half on loan in League One with Oxford United and Charlton Athletic respectively.
Lee was a huge part of the Addicks’ resurgence under Johnnie Jackson this season and there was a point when a permanent move to The Valley felt more likely than not.
However, the 27-year-old lost his place in the first team as the Addicks struggled with inconsistency in the second half of the season and therefore a return to South London seems unlikely this summer.
Lee’s versatility, creativity and experience at the level should make him an attractive proposition for the vast majority of League One clubs, on a free, this summer.
Regular playing time could be hard to achieve for the striker turned central midfielder in the Championship and therefore a two-year deal at a club with aspirations of winning promotion to the second tier would be a sensible move at this stage of his career.
Quiz: Can you name which club Luton Town sold these 16 players to from the last decade?
There was fierce competition for places in midfield areas at Charlton Athletic this season, despite finishing in a very modest 13th place.
Albie Morgan and Scott Fraser were jostling with Lee for a starting berth in the second half of the campaign, but neither were able to nail down the spot as their own.
It was a particularly difficult environment for a loan player at Charlton this season, with frustration from the stands apparent the majority of the way through the campaign, due to the underwhelming results of the team.
Despite falling out of favour, and picking up an injury at the business end of the season, the attack-minded midfielder should find a club towards the top end of the third tier once again this summer.