Harper has made 18 appearances this season
Newcastle goalkeeper Steve Harper may need surgery to resolve the knee problem that kept him out of the midweek draw against Manchester United.
Harper, 36, will not play against Blackpool on Saturday and Toon boss Alan Pardew says he could need an operation for the injury.
Pardew said: "Harper isn't right and we will have to review him over the next couple of weeks.
"It could be that he needs a small operation."
Pardew stressed that the injury does not necessarily signal the end of Harper's season.
"It's not a major problem, but we will have a look at that and weigh that up over the next couple of weeks," the former West Ham manager said.
Dutch keeper Tim Krul will replace Harper in goal at Bloomfield Road, with third-choice stopper Ole Soderberg providing cover on the bench.