The Eels' problematic right-edge defence reared its ugly head again in last week's finals win over Newcastle, letting Enari Tuala in for a hat-trick.

But it wasn't their first issue.

Constant personnel changes on that side of the field through both the halves and centre-wings, Parramatta have continually found themselves in trouble this year.

Reuben Garrick, Brian To'o and Tuala have scored hat-tricks on them in the past two months, while Josh Mansour also claimed a double in round 21.

Which spells even bigger problems for the Eels, when you consider Penrith's left edge is one of the most dangerous in the competition with Jarome Luai, Matt Burton and To'o.

"Yeah, it's really important," Arthur said.

"A couple of those tries that we had scored against on the right edge last week, one of them was off a kick and sometimes there's not a lot you can do about that.

"Another one was when we had a couple of players out of position but we still need to be able to handle it.

"And then the other one, our right edge was in really good position we had the numbers, we just come up with the wrong decision.

"It's in those big guys we have to come up with the right decision more often than not.

"Especially when we're tired and we're under fatigue and there's pressure against us, you've got to come up and we've got to get those moments in those games right."

Penrith meanwhile have their own decisions to make on that side of the field.

Viliame Kikau is again listed to start, but has dropped back to the bench in recent weeks to allow for a second row of Liam Martin and Kurt Capewell.

Kikau had a big impact in his first two games going back to the bench, but his numbers and workload have dropped significantly in the past fortnight.

Coach Ivan Cleary would not say when asked on Friday how he would play the left edge position, and also attempted not to overplay the importance of that battle.

"We've looked at a bunch of things, both edges are important, our middles are important, everyone's just got to play a bit better," Cleary said.

Australian Associated Press