The German forward previously spent two years in the Premier League after joining Chelsea from Leipzig for £45m in 2020.
During his time with the clubs, Werner won the Champions League, UEFA Super Cup and the FIFA Club World Cup, while he also picked up a runners-up medal in the FA Cup and the EFL Cup.
Although he won three trophies with the West London side, Werner struggled to consistently find the net, especially in the Premier League, where he scored 10 goals in 56 top-flight appearances.
Werner subsequently returned to Leipzig in 2022, and he made a significant impact in his first season back at the club, scoring 16 goals and providing six assists in 40 competitive games.
However, the 27-year-old has fallen down the pecking order this season, having started just four of his 13 appearances across all competitions.
With the likes of Lois Openda, Yussuf Poulsen and Benjamin Sesko above him in the pecking order, Werner's future at the Red Bull Arena has been called into question.
According to journalist Florian Plettenberg, Manchester United are one of the clubs that are showing an interest in the former Chelsea man.
The report claims the Red Devils have already made an enquiry about his availability, although they have made no formal offer or held any negotiations at this stage.
Spanish giants Real Madrid have been linked with a potential move, but their interest has reportedly cooled in the German forward.
A recent report stated that Werner is also on the radar of Premier League trio Crystal Palace, Fulham and West Ham United.
While Werner is not happy with his lack of playing time, he is leaning towards staying with Leipzig until at least the end of the season.
Leipzig are set to face Manchester City in the Champions League on Wednesday, but Werner will not be involved after he missed Saturday's defeat to Wolfsburg with an injury issue.