The Germany captain is on the road to recovery after an ankle injury ruled him out for much of the first half of the season and he expects to be fit to make his comeback for Bayer Leverkusen in their first match of 2011. However, Bierhoff has warned him that he will still have to prove himself before returning to the Germany set-up.

"We know about his personality and his excellent qualities, which are good and important for the team, but he also knows that a player who has been out for such a long time will first have to reintegrate with a newly-formed team," he told the Suddeutsche Zeitung newspaper.

Ballack remained captain of the national team despite missing the FIFA World Cup due to injury, although Philipp Lahm has worn the captain's armband in his continued absence. Lahm has made no secret of his desire to remain as captain even when Ballack is back and Bierhoff has suggested that may not be a bad thing for Ballack.

He said: "Maybe he realises that it would do him good if he did not have all of the pressure on him alone. He can also see that as a positive aspect and continue to play at a high level in a functioning team."

Nevertheless, Bierhoff would never close the door on the former Bayern Munich and Chelsea midfielder returning to the national team since he knows how ambitious the 34-year-old is. "The most important thing is [being able to] integrate in a team, but Ballack can do that," he added.