Switzerland striker Johan Vonlanthen has divided medical opinion after results of his MRI scan were published on Tuesday.
The 20-year-old suffered a hamstring injury at the team's pre-World Cup training camp, leading coach Kobi Kuhn to call Hakan Yakin back from his holidays as a replacement.
Kuhn now has to decide whether to reinstate Vonlanthen or stick with Yakin.
Heinz Buhlmann, the doctor who has treated Vonlanthen since last Sunday, said: "Johan Vonlanthen can resume training. He does not suffer any more acute pain.
"However he will evidently be short of preparation."
Buhlmann was the doctor responsible for Martina Hingis' return to top level tennis, but his medical counterpart on the Swiss national team, Cuno Wetzel, does not believe Vonlanthen should be included.
"The result of this MRI scan does not mean that Johan is ready to play a World Cup encounter," he insisted.
"The player was the victim of a torn muscle. The recovery period for such an injury is four weeks."