The Parramatta Eels have confirmed that skipper Clinton Gutherson has undergone a minor operation to repair his injured knee.

In undergoing the operation, the club has confirmed that he will spend at least one month on the sidelines.

"The Eels Co-Captain has undergone a minor operation on his knee and will be unavailable for 4-5 weeks," a statement from the Eels read.

The news adds further woes to the under-performing Eels, who will still be without halfback Mitchell Moses until Round 12 due to a foot injury.

It is understood that Gutherson has been plagued with the knee injury for several weeks - having fluid drained out of knee -ย  and comes after he had surgery at the back end of last year to repair his meniscus.

In what is a significant blow, the club don't have a clear backup fullback to take over from Gutherson.

Daejarn Asi and Blaize Talagi played the position during the pre-season and NSW Cup, while Bailey Simonsson and Sean Russell could easily adapt to it.

The club's skipper will join the growing injury list that includes Bryce Cartwright (rib), Haze Dunster (Lisfranc), Toni Mataele (hamstring), Ofahiki Ogden (pectoral tear), Arthur Miller-Stephen (knee), Richard Penisini (ACL) and Moses (foot).