Ivory Coast international, Jean-Philippe Gbamin has suffered a torn muscle fibre in the adductor area during the Bundesliga match between Mainz versus Stuttgart on Sunday.
The 22-year-old Ivorian midfielder was substituted shortly before the end of the first half.
According to the result of a comprehensive examination at the Mainz University Hospital on Monday, they expect Gbamin to take a break for at least three weeks.
Gbamin recently extended his contract in Mainz, despite offers from the Premier League.
He came to Mainz in summer 2016 and has played 56 league games, scoring a goal and three assists.
Gbamin played in the junior age grades of the French national team before committing to Ivory Coast, the country of his birth, in April 2017.
He has made four appearances for the Elephants of Ivory Coast.