In the cruellest blow of the pre-season so far, Penrith prop Sam McKendry may have re-ruptured the same anterior cruciate ligament that ended his 2016 season.

The 27-year-old's 2016 season finished in Round 17 after suffering an ACL injury against Wests Tigers and looks to have suffered a repeat of the same injury in his side's 18-6 trial win over the Eels on Saturday night.

The hit-out was McKendry's first since suffering the original injury; after being injected into the game at around the 20-minute mark of the trial he stayed down after a tackle shortly before half-time and had to be assisted from the field.

The eight-Test Kiwi will go for scans on Monday with the club hoping for the best but fearing the worst.

"We still hold some hope that it mightn't be the ACL," coach Anthony Griffin said after the game.

"I thought watching it it was more a knee clash than a bend of the knee. But the doctor said he thinks it's possible he's done his ACL again. We'll wait and see… It's terrible. Unfortunately that's the game we're in."

Griffin backed McKendry to come back again even if he had to face another season on the sidelines rehabilitating a knee reconstruction.

"He's rehabbed himself well. He's still relatively young as far as front-rowers go, in his late twenties. He's still got plenty of years in front of him. It's just unfortunately... it's just rugby league. It's what happens," Griffin added.

It continues a horror run for Penrith and knee injuries with the club having lost centres Dean Whare and Peta Hiku to ACL injuries last year. Both of those players got through Saturday's trial against the Eels unscathed as their comebacks continue to gather pace. Winger Josh Mansour did his ACL while on duty with the Kangaroos late last year and winger Dallin Watene-Zelezniak is currently enduring a shorter lay-off with a less serious knee injury.

Penrith also lost hard-running forward Sitaleki Akauola to a nasty concussion on the night after he came off second best attempting to tackle Eels forward David Gower while centre Waqa Blake looked to pick up a leg injury during the game. He shifted to wing rather than coming from the field but looked hampered.

For the Eels, co-captain Beau Scott came off after rolling his ankle but is not in doubt for Round 1.