Hertha Berlin are hopeful that John Brooks will return to full fitness in time for the Bundesliga match at Hoffenheim on Sunday.
Third-placed Hertha travel to fourth-ranked Hoffenheim, who are currently undefeated.
The United States defender picked up a knock in the mid-week DFB Pokal 2-0 win over St. Pauli and is one of many injury doubts for the capital club, who trained on Thursday without three of the usual back-four starters.
Brooks started in Hertha's last three games after serving as an unused substitute following his return at the beginning of this month from a muscle injury.
Hungarian coach Pal Dardai on Sunday will have to do without left-back Marvin Plattenhardt ,who is sidelined with a muscle tear, while both centre-backs, Brooks and Sebastian Langkamp, could still return in time for the match at Hoffenheim.
"Jay [John] told me that he will return in time," Dardai said of the U.S. defender, who picked up a knock in mid-week's cup win at FC St. Pauli.
The coach added of Langkamp: "I can't really say anything about him."
Both players trained individually on Thursday.
Dardai also hopes that former club captain Fabian Lustenberger can return against Hoffenheim after missing the last three matches because of a bruise.
"Lusti trained with the ball for the first time today. It looked good. We need to see how his body reacts," the coach said.
Hertha have made their best ever start to a Bundesliga campaign with five wins, two draws and only one defeat at Bayern Munich.
Hoffenheim have equalled their best-ever start, and have earned 16 points from their first eight matches during their first year in the German top flight in 2008.