The Toon lost 3-2 on Monday night, with midfield pair Sandro Tonali and Joelinton forced off in the second-half due to injury.
Advertisement
Advertisement
Howe said on DAZN afterwards: "Difficult for me to give a thorough assessment at the moment, but Joelinton's doesn't look good.
"Sandro Tonali's doesn't look good. Obviously, Anthony Gordon will now be suspended for, and Fabian (Schar) looks concussed."
Howe later told Sky Sports: "Sandro's doesn't look good, he was in quite a bit of pain. I don't know the full extent of it or Joelinton's.
"They both look threatening for us in the sense they could be out for a while."