Javier Hernandez
Hernandez suffers knee injury on international duty.Reuters

Shinji Kagawa and Javier Hernandez will return to Manchester United from international duty with fresh fitness concerns.

Hernandez was forced off at half time during Mexico's friendly with Nigeria with a suspected sprained knee after colliding with opposition goalkeeper Vincent Enyeama.

The 25-year-old admitted he was concerned over the knock and Mexico's team doctor is unsure of how long the striker may be side-lined for, although he was able to rule out a ligament strain.

"Development are to be expected to find out how serious the injury is," Jose Vasquez was quoted as saying by Mexican newspaper Excelsior. "We do not have an estimate of how long he could be out for because we need to see the tests.

"Now he has pain, but it is not unstable."

Kagawa enjoyed a superb evening in Tokyo as he played an instrumental role in helping Japan storm to a 4-0 lead over New Zealand inside 17 minutes. The United playmaker assisted the first and won a penalty after a jinking run into the box before slotting home his side's second.

The playmaker was taken off after 79 minutes but admitted the second half of the World Cup warm up game left him feeling drained, calling into question the 24-year-old's match fitness having spent so much time on the Manchester United bench this season.

"It had been a while (starting a match)," Kagawa told reporters, Goal.com report. "But I still had to play well and earn a good result whether I started or came off the bench. I didn't feel as strong in the second half so that's something I have to consider."

There was concern earlier in the week when Holland head coach Louis van Gaal revealed Robin van Persie was suffering from illness and would likely miss Wednesday's clash with France. However the striker recovered in time to start in his side's 2-0 defeat at the Stade de France and is likely to be fit for the visit to West Brom on Saturday.

In the same match, there was a brief moment of concern when Patrice Evra was caught by the high boot of Dutch midfielder Quincy Promes. Although the full back was replaced by Lucas Digne at half time there has been no suggestion of injury and he is also expected to feature at the Hawthorns on Saturday.