Alexander lamented the losses of second-rower Viliame Kikau and hooker Api Koroisau, but says they have quality replacements lined up.

Promising new signings Luke Garner, Zac Hosking and Tyrone Peachey are all in the frame for the vacant second-row position, while Peachey and rookie Soni Luke can provide important back-up for the No.9 role.

But Alexander backed 24-year-old Mitch Kenny to make the position his own.

"Mitch did a great job starting through the finals series and late in the year," Alexander told AAP.

"He's fit, he's tough, he's got a good passing game coming out of dummy half."

Alexander believes the Panthers have done a good job at maintaining a strong core of top-class players, despite the turnover.

"When you look at the Penrith side there's probably eight or nine players who are in the top two or three in their position throughout the league," he said.

"All clubs that have had success have struggled to hang onto players. We lost two last year and we lost two again this year.

"When you have so many players that can demand top dollar for their position, it's very hard to keep them."

Alexander, who coaches in the NSW Blues set-up, said he would not like to see Australian-born Pasifika players become ineligible for State of Origin if they play for their country of heritage.

Penrith players Jarome Luai, Brian To'o and Stephen Crichton could miss out on Blues selection if Samoa became a tier-one nation, an eventuality Alexander hopes would not come to pass.

"They grew up in Western Sydney playing footy, they're Penrith juniors," he said.

"I dont think we could change that.

"Under every criteria to play for the Blues they qualify so the fact they played for Samoa in the world cup I don't think should make those players ineligible."

Australian Associated Press