Luton are in talks with Birmingham over winger Tahith Chong, who only moved to St Andrew's last summer.
The Hatters are also discussing moves for Barnsley's Mads Juel Andersen and Aston Villa's Marvelous Nakamba.
Chong, 23, came through the Manchester United academy, making 16 first-team appearances for the Old Trafford club.
The Curacao-born player spent the 2021-22 campaign on loan at Birmingham, who then signed him permanently last summer.
Chong scored four goals and contributed five assists in 41 appearances for Blues last season as they finished 17th in the Championship table.
Luton won the play-offs to secure top-flight football for the first time in over three decades, with Rob Edwards eager to strengthen his squad so they can compete at the top level.
The Hatters will open their Premier League campaign with a visit to Brighton on August 12.
Danish centre-half Andersen has made 167 appearances for Barnsley over the past four seasons and was named in the League One team of the season for 2022-23 following impressive performances.
The Tykes reached the play-off final but lost in agonising fashion to South Yorkshire rivals Sheffield Wednesday at Wembley.
Zimbabwean defensive midfielder Nakamba, 29, spent the second half of last season on loan at Luton from Aston Villa, helping them win promotion and Edwards is keen to keep him.
