Arthur said the NSW State of Origin star was not likely to take on Gold Coast next week, and his loss prompted Beau Scott to be moved into the backline.
The Panthers immediately zeroed in on Scott and ran in three tries in 11 minutes down the Eels' right edge.
Winger Josh Mansour was immense for the Panthers.
He ran for a game-high 229 metres and took 20 valuable hit ups to take the pressure off his forwards who did a mountain of work in the first half anyway.
Mansour also broke 10 tackles and scored the match-winner.The two points moved the Panthers into ninth - only behind eighth-placed Warriors on for-and-against.
Their quickfire comeback was a show of strength and several top eight sides will be looking over the shoulders however coach Anthony Griffin said he wasn't satisfied, accusing his side of being patchy at best.
"No disrespect to Parramatta - they were fantastic," Griffin said.
"But we played for 20 minutes in the second half but the rest of it was pretty ordinary.
"A massive rap on our defence and scramble to hold them out at the end there."
Clint Gutherson, standing in for the suspended No.6 Corey Norman, was a shining light for the Eels.
Despite being the side's seventh-choice playmaker and not having played in the halves since under-13s, he laid on his side's first two tries and scored one himself.
Arthur refused to lay blame for the loss at the feet of their injuries and instability.
"On Thursday we weren't sure if Jenko was playing so Beauie did a bit of work at right centre and Manu (Ma'u) on the left and then on Saturday we had to swap them back around again," Arthur said.
"It wasn't ideal but that wasn't the reason why we didn't win. In the second half we completed at 59 per cent."
Penrith prop Reagan Campbell-Gillard suffered a hyper-extended elbow in the second half and is not expected to take on Brisbane on Friday.
- AAP
