Celtic were linked with a move to sign McCarthy from Everton.
Celtic were reportedly interested in signing Everton midfielder James McCarthy in the January transfer window - and they will be wishing they had done more than ever after the injury to Emilio Izaguirre.
TeamTalk claimed in January that Celtic had made an approach for the 28-year-old, who has failed to make a single appearance under Marco Silva at Goodison Park this season.
The Ireland international has returned from a horrific leg break after a year on the sidelines, when Salomon Rondon went to shoot for West Bromwich Albion - only connecting with McCarthy's leg.
Celtic were not alone in their pursuit of former Hamilton product McCarthy, with Premier League sides West Ham United, Crystal Palace and Fulham, as well as Championship sides West Brom and Derby keen.
But Brendan Rodgers' side will surely be wishing they had signed McCarthy, with Izaguirre suffering an injury during the 2-0 win over Hibernian on Wednesday night in the Scottish Premiership.
The Honduras veteran had been filling in for Kieran Tierney, who is also sidelined through injury. It means that Callum McGregor is likely to give up his midfield role and play at left-back, which he has done in the past.
Celtic have four very crucial games coming up, with a Scottish Cup clash against St. Johnstone on Sunday before two legs against Valencia - separated by a Scottish Premiership clash against Steve Clarke's Kilmarnock.
McGregor moving to left-back leaves an important hole in the middle of the park, and McCarthy - who joined Everton from Wigan in 2013 for £13million (Mail) - would have been the perfect replacement.
However, Rodgers and Celtic will have to do without in the last 32 of the Europa League. But McCarthy would have certainly been a perfect January signing, even more so now.