Michael Owen has been ruled out of Newcastle's clash with Sunderland on Saturday.
Owen hurt his groin in training earlier this month but Joe Kinnear had been keen to give him every opportunity to recover.
However, the interim manager has decided not to risk the striker at the Stadium of Light, with next Tuesday's home game against West Brom now a possible return date.
"Michael, unfortunately, will not be fit in time for Sunderland and, of course, that's a blow to lose a striker of his calibre," Kinnear told the club's official website.
Argentine winger Jonas Gutierrez, who has been sidelined with a broken collarbone, also remains doubtful.
Kinnear will give Gutierrez until Friday to prove his fitness but is not sure if he will be ready.
"As far as Gutierrez is concerned, I would say he is 50-50," Kinnear told the Evening Chronicle.
"However, we are prepared to give him every chance.
"I will assess him over the next 24 hours as to whether he starts from the bench or not.
"I love the look of him in training and look forward to seeing him in action."
Nicky Butt has declared himself fit despite requiring stitches in a nasty ankle gash following the 2-2 draw with Manchester City on Monday.
The stand-in skipper missed the corresponding fixture last season and is looking forward to the challenge.
"I needed a few stitches in my ankle but I'll be okay for the derby," Butt told the club's official website.
"It's my first at the Stadium of Light because I missed the last one because of suspension and it will be an honour to captain the side."