Uruguay and Gremio striker Luis Suarez, who suffers from osteoarthrosis in his right knee, is struggling to extend his playing career, according to his Brazilian club's president Alberto Guerra.
The former Barcelona player is considering retirement, Brazilian media reported, as he suffers from severe pain that forces him to take injections to play.
"It is serious. Suarez has the possibility of being fitted with a prosthesis," Guerra told reporters at Gremio's stadium.
"He's had a lot of injections, a lot of medication, he's reaching the limit, when is the limit? We don't know."
The 36-year-old Suarez is still training and was named in the Gremio squad to face America-MG on Thursday in Brazil's Serie A.
Suarez, who has a contract with Gremio until December 2024, arrived at the Porto Alegre-based club in January and has scored 11 goals in 25 games.
Suarez has also been linked with a move to MLS side Inter Miami, where he could join up with Lionel Messi, his close friend and former teammate.