Callum Wilson, a Newcastle striker, had chest surgery and may miss a significant portion of the remaining games.
The 31-year-old England international was injured in the pectoral muscle during Saturday's 3-2 Premier League victory over Nottingham Forest.
This season, he has played 22 games for Newcastle across all competitions and scored eight goals, but he has struggled with hamstring and calf issues.
"It is a major setback for him," Eddie Howe, manager of Newcastle, stated.
"He's had an inconsistent season. We're hoping he returns before the season concludes."
Wilson participated in the entire Forest match, but he constructed a sling out of his shirt in the last moments.
It was an unusual wound. At the last game's conclusion, he got into a brawl with the center back, Howe said.
"We had it scanned and was hoping first of all he should continue, however, while he went to look for an expert I assume it became obvious pretty early that he wished it running on."
On Saturday, Newcastle, currently ranked seventh in the league, will face Bournemouth.