Report: Cristiano Ronaldo's knee troubles a growing concern

Real Madrid are reportedly becoming increasingly concerned with Cristiano Ronaldo's inability to shake off a knee problem.

The Portuguese international has struggled with tendonitis this season, but the forward has not had an extended period on the sidelines.

According to Marca, Ronaldo has pain whenever he sprints and has been advised to spend six weeks on the sidelines, but that is not said to be a consideration at this stage of the campaign.

Ronaldo has recently undergone tests on his troublesome knee, but Real Madrid are said to be keen on dealing with the issue in-house.

The 30-year-old has scored 36 times in 32 games for his club this season, but the goals have not come as freely in recent matches.