Northern Ireland's Craig Cathcart and Michael Smith are injury concerns for this month's Euro 2020 qualifiers against the Netherlands and Germany.
Cathcart came off 20 minutes into Watford's Premier League defeat by Chelsea on Saturday with a back spasm.
Hearts full-back Smith also had to be substituted during his side's League Cup semi-final loss to Rangers on Sunday after a quad injury.
NI play the Netherlands at Windsor Park on 16 November.
Michael O'Neill's third-placed side, who are three points behind the Dutch leaders, then travel to Frankfurt to take on the Germans in their final Group C qualifying match three days later.
Speaking after their 2-1 defeat at home to Chelsea, Hornets boss Quique Sánchez Flores did not reveal the extent of Cathcart's injury, but told the Watford website that the centre-half did not have any problems with his back before the game.
Blackpool midfielder Jordan Thompson, who started for NI in October's friendly win over the Czech Republic, sat out his side's win over Peterborough on Saturday after picking up a knock during the week.
Blackpool boss Simon Grayson told the Blackpool Gazette that he rested Thompson as a precaution and he is expected to be fit if selected for international duty.
Northern Ireland conceded two injury-time goals as they lost 3-1 to the Netherlands in their last Euro 2020 qualifier in Rotterdam last month.