Will Grigg has been ruled out of Northern Ireland’s Euro 2020 qualifiers against Estonia and Belarus through injury.
The 27-year-old striker, capped 13 times, has returned to Sunderland for treatment, though the nature of the problem has not yet been disclosed.
Blackburn midfielder Corry Evans also missed training on Wednesday morning and remains a doubt for Thursday’s match with Estonia due to a hamstring problem.
Grigg had been recalled to Michael O'Neill's squad after also missing the last three games of last year through injury.
His absence leaves O’Neill with Kyle Lafferty, Liam Boyce, Josh Magennis, Conor Washington and the inexperienced Paul Smyth as options in attack.
Northern Ireland open their Euro 2020 qualifying campaign against Estonia before playing Belarus on Sunday, with both matches at Windsor Park.