Jack Colback is doubtful for Newcastle United's FA Cup tie against Watford.
The midfielder has a hamstring problem is unlikely to feature in the third-round tie at Vicarage Road.
Head coach McClaren, however, has again insisted that he will name a strong team in the competition.
“I think we have one or two players who have niggles, and it is a big risk so we have to decide whether to play them or not," said McClaren, whose side take on Manchester United at St James's Park on Tuesday night.
"Tomorrow will be the strongest team we will be able to put out without taking risk.
“Jack Colback could be next week, but generally wear and tear from the season and the Christmas period.
"You have to manage these three games, and that’s the key thing for these games. We need to have enough in the team, enough attitude to get the results in these three games."