Manchester United winger Cristiano Ronaldo believes he could be playing again by the end of September. The Portuguese underwent ankle surgery in July and initial forecasts were that he could be out of action until late October and possibly November. But Ronaldo, who scored 42 goals last season to fire United to the Premier League title and Champions League, has been told to step up his rehabilitation after making better-than-expected progress. 'I am feeling fine. I am feeling really good and my recovery is going well,' the 23-year-old said. 'I am more than happy with my progress and I hope to be back playing for United by the end of September - that is my target and it is a realistic one. 'It has been frustrating to miss the start of the Premier League season but I am pleased with my rehabilitation and, hopefully, I'll be ready soon.'