Croker said it was a frustrated best finishers and hopes the club could take advantage of the new rule by signing an additional outside back.
"I caught up with him yesterday but why I was still in pretty good spirits," Croker said.
"It's very disappointing for Jordan, the best winger in the world, or up there anyway.
"To lose him for probably the first half of the season is extremely disappointing. It gives someone like Michael Oldfield a chance but it also makes that backline a little bit skinny.
"Outside backs is probably not that much of depth. Michael Oldfield, we saw what he could do last year, he's a first grader every day of the week, but yeah it would be nice to add a bit more depth to the stocks that's for sure.
"We didn't get any luck last year with Hodgo doing his knee international and to have two blocks doing the same thing representing their country, it's frustrating but that's the game isn't it."
Rapana joins hooker Ata Hingano on the long-term injury list after he also injured his shoulder playing internationally and went under the knife last week.
It was the second time, the first six games of the 2019 season.
Furner confirmed they won't ask the NRL for compensation for Hingano but said it was too early to make a call on Rapana.
"We'll look at it down the track once we see how the surgery goes," Furner said.
"The doctor could come out and say I could come out and say it looks really bad, so we need to get all that out of the road.
"But our plan would be, if it's going to be six, seven or eight months, we would definitely look at it. But hopefully we don't have to use it and he's back [sooner].
"It's going to be a long process before we put any applications in [the NRL] and I will get any type of relief, I don't know. "
Eamonn Tiernan is a sports reporter with The Canberra Times