The Dutchman suffered the knock while on international duty with Netherlands last week, and was forced to miss his side's Bundesliga clash with Mainz on Saturday.
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However, the former Real Madrid man has made a swift return to training, but remains unsure whether he will be able to line up at the Allianz Arena on Wednesday.
"It's looking good," he told FCB.tv. "It's something in my back, which made my groin feel bad.
"We have to be reasonable and smart now because we have so many important matches in the next few weeks.
"I'll have to wait and see. We're taking each day as it comes."
Franck Ribery also missed the weekend's match with a muscle strain, but is looking more likely than his Dutch team-mate to feature against Valencia.
"I think I'll be able to play on Wednesday," he confirmed.
Bayern Munich play Valencia in Group F this Wednesday, September 19.