The hospital treating Boris Vukcevic confirmed on Monday that the midfielder's conditions remains "critical but stable" after a series of operations.
Vukcevic was induced into a coma after being badly injured in a car crash on Friday.
Hoffenheim posted a statement from Heidelberg University Hospital on their official website, which read: "Boris Vukcevic was taken to Heidelberg University Hospital after his accident on Friday, September 28 2012 and is being treated there.
"After two operations on the head and brain, his condition is critical but stable. A prognosis is not possible at this stage and will likely only be possible in the next weeks. Vukcevic is in a coma. His doctors are doing everything to protect the brain from further damage."