The Stuttgart right back was injured early in the match and has partially torn a ligament in his ankle.
Gotoku Sakai suffered a partially torn ligament in his right ankle during Stuttgart's match on Sunday. He will have an MRI scan completed Monday to determine the full extent of the damage. At this time, the club is unable to determine how long he'll be out of action.
Sakai, 21, was injured early in the match after a collision with Eintracht Frankfurt's Martin Lanig. He was already carrying a different, small injury into this match, but he managed to stay on the pitch for the full 90 minutes.
The Japanese defender is currently on a year and a half long loan to Stuttgart from J League club Albirex Niigata. They will have the option to make his loan a permanent transfer in June 2013 when the loan expires.
If Sakai is forced to miss any significant time, Bruno Labbadia will have to decide if he wants to play Tim Hoogland or switch Arthur Boka over from his more natural left back position.