Scans have revealed Everton midfielder Gareth Barry has sustained ankle ligament damage but it is still too early to put a timescale on his predicted recovery.
The 33-year-old was carried off just 13 minutes into Sunday's 1-1 draw at Sunderland after a late tackle by Jordi Gomez and - although initial fears of a broken leg were allayed quickly - Barry has not escaped unscathed.
Press Association Sport understands preliminary examinations have identified damage to the right ankle but Everton's medical team will have to wait for significant swelling to subside before they can make a better assessment of how serious the injury actually is.
With James McCarthy sitting out Republic of Ireland training on Tuesday after complaining of a hamstring problem after the match at the Stadium of Light, manager Roberto Martinez will be watching the forthcoming internationals closely.
Everton later released a statement on their website which confirmed the player would continue to be assessed.
"The player's treatment at Finch Farm is ongoing and although it is too early to estimate a length of absence, it is hopeful the time out will be weeks rather than months," it said.