Lewis pulled up early in the game holding his hamstring, and was replaced by Matt Ritchie.
The left-back – who had come into the team when Ritchie was suspended last month – is now being assessed ahead of the club’s bust festive programme.
“It looks bad – it looks like a hamstring problem,” said head coach Eddie Howe. “It’s a surprise with Jamal, because he’s obviously so athletic. He’s been excellent in terms of his athletic work for us.
“Obviously, it was damaging to lose a sub so early in the match. I thought Matt Ritchie came on and was fantastic in his place. Certainly, it’s not the time of year for us to lose players. Fingers crossed, it’s only Jamal that will probably go into the Christmas period now in any doubt, but we need to check on a few others that were carrying things.”