Key Penrith recruit Jamal Idris is set to miss the start of the NRL season due to a hamstring injury.
Idris suffered a suspected grade one hamstring tear in the Panthers 52-4 win over NSW Cup side Newtown on Sunday.
One of a host of big off-season buys for the Panthers, the former Gold Coast and Canterbury centre was brought to add crucial size to Penrith's outside backs.
But the former NSW representative is likely to miss at least Penrith's round one clash with Newcastle on March 8 according to coach Ivan Cleary.
"He has a bit of a hamstring strain but I don't think it's too bad," Cleary said.
"It is going to be a bit of a struggle for round one.
"But it is a long year so we will see how it goes."
Idris will undergo scans on Monday to determine the full extent of the injury.
Josh Mansour, who scored four times for Penrith in the ten-tries-to-one rout, was among the best on ground, along with teammates Kevin Kingston and Tyrone Peachey.
The match was the first for Sydney Roosters' Kiwi representative winger Roger Tuivasa-Sheck after he fractured his leg in the World Cup final.
The international winger of the year played only the first half at fullback on doctor's orders after being ruled out of the Roosters' World Club Challenge clash with Wigan on Saturday.
The Panthers have had an indifferent pre-season after fielding a largely second-string side in their first trial loss to Wests Tigers.
Against Newtown, in their second and final trial, their structures looked solid and in the absence of Jamie Soward (ankle) halves Isaac John and Peter Wallace combined well.
Soward is expected to be fit for round one but Cleary admitted he didn't really know how his side was travelling two weeks out from the start of the premiership.
"There were some good things out there and there should have been," Cleary said.
"We definitely have to improve, we didn't push as much in defence as we could have.
"But it's pre-season. Until you play a game but don't really know.
"It was good practice. It's a bit of a challenge (to stay focused) in a game like that when you get out to a big lead.
"We learned a fair bit about some of the levels we have to get to."