Bayern Munich winger Arjen Robben returned to team training on Thursday after undergoing groin surgery in October and missing much of the season before that with another injury. The Dutchman, who has only once managed to play the full 90 minutes in the league this season, trained for 45 minutes with his team mates before undergoing individual fitness training, the club said.    \"We will have to see from day to day how the groin reacts to this,\" Bayern assistant coach Peter Hermann said.Bayern have been playing well even without Robben and lead the Bundesliga standings with a five-point gap while also topping their Champions League group. Robben, who helped Bayern to the league and German Cup double as well as the 2010 Champions League final in his first season, has been plagued by injuries since the Netherlands lost in the 2010 World Cup final to Spain.\"Robben is an important player in our team. It will be good when he is back,\" captain Philipp Lahm told reporters.