Steve Bruce has been rocked by two injuries during the 1-1 draw with Aston Villa at St James' Park.
Second-half withdrawals for Matt Ritchie and Isaac Hayden were precautionary but Bruce has confirmed that both have suffered "soft tissue" problems.
Ritchie was immediately handed an ice pack after coming off and is a doubt for the FA Cup tie against Manchester City.
After the game Bruce said: "They're both soft tissue.
"We will have to wait and see.
"We hope we’ve caught it (in time), it’s more precautionary.
"We have to err with caution.”
Reflecting on the late equaliser at St James', Bruce said: "We’re disappointed. It’s the first goal we’ve conceded in five games (at home).
"If somebody had said we’d take four points from these first two games, I’d have accepted it.”
