Ameobi has scored five goals in all competitions this campaign

The 25-year-old has not played for two weeks because of the problem and now looks likely to undergo surgery.

Roeder said: "We're close to booking an operation in America. When he has it, that's him out for the season."

The manager also revealed that reserve keeper Tim Krul could face a spell on the sidelines with a knee injury.

The 18-year-old, who made an impressive debut in the Uefa Cup against Palermo last week, aggravated the problem in the warm-up for the Magpies' Carling Cup win over Watford on Tuesday.

We were not 100% certain that there wasn't some sort of cartilage damage, and sure enough it looks like that has surfaced Roeder on Krul

Roeder said: "Tim got injured before the game in Italy last week, and we weren't sure then whether he had damaged his cartilage or just had a bang on his knee.

"He was able to play against Palermo and had the most wonderful debut but we were not 100% certain that there wasn't some sort of cartilage damage, and sure enough it looks like that has surfaced.

606: DEBATE Yet more bad news on the striker front, who should Newcastle look at signing? FS 606: Have your say

"He made a save in a warm-up session and the knee locked as he got up and he was in a lot of pain.

"He has been taken to hospital and if he needs anything done, then it will be done in Watford."