Bayern Munich star Arjen Robben could retire at the end of the season, the 33-year old has suggested.Although he says his future is yet to be decided, but has admitted he could call it quits at the end of the season.The former Chelsea and Real Madrid winger retired from international duty in October as Holland failed to reach the 2018 World Cup, and he could now retire from the game entirely as his contract with Bayern runs out at the end of the season."The future is open!" Robben told Kicker. "It may be over after this season, something new may come or I'll play three more years at Bayern. Everything is possible. "The appreciation between Bayern and I has always been there, from both sides. I know what I have at this club, and I always say that."I just look to the next game, not beyond. I want to try to have fun as long as I can and play football at a high level, I do not know how long that will go on."Robben picked up an injury in Wednesday's Champions League win at Anderlecht, but is not expected to be out for long, according to coach Jupp Heynckes.He has suffered consistent muscle issues in recent years.