Thomas Tuchel has several fitness concerns ahead of Borussia Dortmund's clash against Hoffenheim, with Pierre-Emerick Aubameyang struggling through illness while captain Mats Hummels and Lukasz Piszczek are injury doubts.
Aubameyang has enjoyed a fine Bundesliga campaign for Dortmund this term and his return of 21 league goals is bettered only by Bayern Munich striker Robert Lewandowski.
However, the Gabon forward has been training away from the squad as a precaution and it remains to be seen whether he will start at Signal Iduna Park on Sunday.
"Aubameyang has caught an infection," Tuchel said at a news conference ahead of the contest with relegation-threatened Hoffenheim.
"He now feels better but, as of now, he is not training with the team because it could be contagious."
Hummels was withdrawn at half-time during Thursday's 1-0 Europa League last-32 second-leg tie at Porto - which secured a 3-0 aggregate triumph - with hip and back problems, while Piszczek missed out altogether with a muscular issue.
"We are still not sure about Hummels' condition," added Tuchel. "We have a couple of players that are doubtful."
Midfielder Ilkay Gundogan was also ill against Porto, while goalkeeper Roman Weidenfeller has been contending with flu and Marco Reus has a slight groin problem.
Tuchel will make a late check on the latter pair, but he says no risks will be taken with any of his players.
"With Ilkay you could see he was not back to 100 per cent against Porto," he commented. "We want to have a fresh set of players on the field on Sunday.
"Hoffenheim played a lot of different systems and shapes. They are highly flexible. I expect Hoffenheim to tactically align to our playing style. We have to work on some individual tactical tweaks."