Southend forward Tom Hopper has ruptured his anterior cruciate ligament and will miss the rest of the season.
The 24-year-old is the League One club's top scorer so far this term, with seven goals in 14 appearances.
Hopper was injured in the 3-0 win over Walsall on October 23 and a subsequent scan has shown he will need nine months to recover after undergoing surgery.
"It's a devastating blow because of the brilliant impression he has made," boss Chris Powell told the club website.
"He's a natural goalscorer at this level and we'll miss him, but first and foremost we want him to get back healthy and fit and that's the most important thing."
In the same game the Shrimpers lost defender Harry Lennon to a broken leg injury, ruling him out until the New Year.