The defender – who has been enjoying an impressive season at Celtic Park – will undergo shoulder surgery tomorrow, having consulted with a specialist yesterday.
The Welshman was carried off after just 13 minutes of Celtic’s 2-0 win over Motherwell at Parkhead on Saturday.
The lengthy lay-off means he will play no further part in the Champions League group stages, with Celtic still due to face Ajax at home and away, AC Milan at Celtic Park, and Barcelona at the Nou Camp.
A statement on Celtic’s website confirmed: “Adam Matthews saw a specialist today and he will undergo shoulder surgery on Wednesday. It’s likely that he will be out for between ten to 12 weeks. Everyone at Celtic sends their best wishes to Adam ahead of the surgery and for the weeks ahead.” The injury to Matthews was also a blow to his country, who are preparing for World Cup qualifiers against Macedonia and Belgium this week.
Wales manager Chris Coleman has been hit by a fresh batch of withdrawals from his squad. Coleman had already lost Gareth Bale, Joe Ledley and Joe Allen due to injuries, while Brighton’s Andrew Crofts is injured and also suspended for the Macedonia match. But a further five players have now joined that list – Matthews, Swansea defender Ben Davies, Wolves’ Sam Ricketts, Crystal Palace’s Danny Gabbidon and Jack Collison, who is currently on loan at Bournemouth from West Ham.
Davies suffered a suspected hamstring injury late in Swansea’s 2-0 defeat at Southampton on Sunday and Gabbidon (hamstring) missed Palace’s trip to Liverpool on Saturday.
The Welsh FA confirmed on its official website a total of nine replacements, including Owain Tudur Jones of Hibs. The others are Lloyd Isgrove (Southampton), Danny Alfei (Swansea), James Wilson (Bristol City), Rhoys Wiggins (Charlton), Jermaine Easter (Crystal Palace), Sean MacDonald (Bournemouth), David Cotterill (Doncaster) and Ashley Richards (Huddersfield).
Coleman will also keep monitoring the fitness of key defender Ashley Williams, the Swansea captain who has been troubled by an ankle ligament problem. Wales play Macedonia in Cardiff on Friday night before heading to Brussels for an appointment with clear Group A leaders Belgium the following Tuesday.
Wales are currently bottom of the group, despite having beaten Scotland twice.
Coleman had agreed terms on a two-year contract extension prior to last month’s defeats to Macedonia and Serbia, but the deal remains unsigned, with the FAW wanting to evaluate performances over the final two World Cup qualifiers.