Arsenal expect defender Johan Djourou to be out for the rest of the season despite suggestions to the contrary from Switzerland, Press Association Sport understands.
The Swiss Football Association posted a statement on their official website on Tuesday suggesting a more positive prognosis than Arsene Wenger's initial post-match comments after Djourou suffered a dislocated shoulder in the FA Cup quarter-final defeat at Manchester United.
The Swiss FA went as far as to suggest the defender could feature in the Euro 2012 qualifier against Bulgaria on March 26, reporting Djourou "had new hope that his season is not over yet" as initial tests showed there were no fractures, while ligament damage was indicated "not to be in a serious condition".
However, it is understood the 24-year-old is in fact expected to undergo corrective surgery later this week following further scans with Arsenal's medical team.
The confirmation of Djourou's absence is another blow as Wenger looks to salvage a campaign which is in danger of falling apart once more.
After suffering Carling Cup final heartache at Wembley, the Gunners then crashed out of Europe in Barcelona before losing at Old Trafford as fighting on four fronts suddenly became just one.
Nevertheless, Arsenal still have the destiny of the Barclays Premier League crown in their own hands, just three points behind United but with a match in hand ahead and a crunch showdown at the Emirates Stadium to come on May 1.
Given Thomas Vermaelen has yet to feature since the end of August because of a niggling Achilles injury, Arsenal will head to West Brom with Sebastian Squillaci set to partner Laurent Koscielny in a pairing which so far has proved less than effective.
Midfielder Alex Song (knee) has already been ruled out, while captain Cesc Fabregas (hamstring) and England winger Theo Walcott (ankle) are not expected to feature at The Hawthorns.
Striker Nicklas Bendtner - again linked with a move away from Arsenal, this time to Blackburn - should be available after missing the United trip with sickness.
Copyright (c) PA Sport 2009, All Rights Reserved.