Bryan Mbeumo has had to withdraw from Cameroon’s squad for friendlies against Australia and China, as a precaution, after being substituted in the 71st minute of Friday night's 2-2 draw with Bournemouth.
Benjamin Sesko has also had to withdraw from international duty.
The centre-forward will miss Slovenia’s friendlies against Hungary and Montenegro, in order to ensure that he fully recovers from an issue that United have been carefully managing throughout recent weeks.
The break includes important World Cup play-offs, as the final slots for the big summer tournament are due to be filled next week.