Bayer Leverkusen's ex-Germany captain Michael Ballack has left the question of his retirement at the end of the season open as he prepares to face Chelsea on Wednesday in the Champions League.
The 35-year-old scored in Leverkusen's 2-0 Bundesliga win over Kaiserslautern on Friday and is now set to face his ex-club Chelsea, who are top of Group E with hosts Leverkusen second.
"This is an important game, because we want to get something," said Ballack, who spent four years at Stamford Bridge.
Ballack is out of contract in June and despite dropping hints this will be his last season, the former Germany star left the question of his retirement unanswered.
"Maybe it was not my last game here," he said after the win at Kaiserslautern.
"I have never said that I want to stop, but if you are 35 years old and your contract expires, it is normal that you are concerned. We'll have to see."
Ballack has endured tough times since his return from Chelsea in July 2010 as he suffered a broken leg on just his third game back in the German league, then struggled to regain form and spent much of last season on the bench.
He missed the 2010 World Cup and has been told by Germany coach Joachim Loew there is no future for him in the national side, leaving him on 98 caps.
He has established himself as a Leverkusen regular this season with two goals in nine league games.
Despite playing with a mask to protect the nose he broke a few weeks ago, his 54th minute strike against Kaiserslautern gave the goalkeeper no chance.
Leverkusen started their Champions League campaign with a 2-0 defeat to Chelsea at Stamford Bridge in September, but home wins over Genk and Valencia gives them a chance of making the knock-out stages.
Bayer goalkeeper Bernd Leno has described Ballack as the "absolute team player", but the veteran says sixth in the German league is not enough and has demanded a top three finish to guarantee next season's Champions League place.
"We have finally showed what we can do for 90 minutes, but a victory alone is not enough," he said.
"We want to return to the Champions League places and we have to act now, which we haven't done recently."