Arsenal manager Arsene Wenger may not be able to give star forward Alexis Sanchez the rest he needs because of a rash of injuries that have struck the team of late.
Sanchez was due to return from international duty with Chile around 36 hours prior to the match at the Hawthorns. Chile lost 3-0 to Uruguay after a 1-1 draw with Colombia during the international hiatus.
Sanchez is becoming ever more important to Arsenal and Wenger wishes to give him some time off, but is unable to at present.
Asked if the former Barcelona forward will be granted some leave, Wenger said: "At some point yes. At the moment I am a bit short because [I have] no Chamberlain, no Ramsey, no Walcott, no [Jack] Wilshere, no [Danny] Welbeck.
"There is not many offensive positions where I can rotate.
"I am worried because when he went to Chile he was already a bit jaded and to see what state he will come back [in], I will have to test.
"But speaking to the player, if I ask him 'are you tired?' you can guess the answer."
Sanchez will not be flying off on national service until March at the earliest, giving Wenger complete control over his welfare.
"That is welcome that there is no international break now," he added.
There has been some good news on the injury front, with right-back Hector Bellerin available following a groin problem.
Wenger will assess Laurent Koscielny and Olivier Giroud's readiness to play after the pair's involvement for France during the international break, when terrorists struck in coordinated attacks in Paris during their friendly against Germany last Friday.
Wenger says defender Koscielny, in particular, appeared affected in Tuesday's match with England at Wembley.