And Morris has provided a flicker of hope for Queensland discard Billy Slater by agreeing that the Melbourne flyer is the NRL's best fullback.
Maroons enforcer Costigan is all but ruled out of contention for May 21's Origin opener after being sidelined for up to eight weeks with a quad injury suffered in Canberra's first round loss.
Queensland warhorse Steve Price is also sweating on scan results for his torn hamstring after lasting just 17 minutes in the New Zealand Warriors' Monday night loss to Slater's Melbourne.
While still hopeful Costigan would wear the Maroons jersey, Morris is not concerned about depth after watching Queensland hardmen Nate Myles and David Shillington run out for the Roosters last Friday night.
"He (Costigan) is obviously a player made for State of Origin - he's got plenty of attitude, aggression and skill," Morris said.
"Obviously he will be missed.
"But we've got plenty of players at this stage that have the attitude and worth ethic that he's got.
Starting prop Shillington and backrower Myles were part of a monster Roosters pack that helped carve out a 34-20 NRL win over South Sydney in their NRL opener.
"It's really up to them to stay fit and keep themselves out of trouble - they've just got to play their game," Morris said of the Roosters duo.
Morris "did not want to put the mocker on anyone" but also agreed with Melbourne coach Craig Bellamy's assessment that Slater was the NRL's No.1 fullback based on his Monday night hat-trick.
Slater on Tuesday said he was not worrying about gaining Queensland selection any more after sweating on a Maroons nod for the past two seasons.
He has not played for Queensland since 2005.
"For Craig to say that I can understand it, and on his form the other night you would have to agree with it," Morris said of Bellamy's assessment of Slater.
"He has always been in the (Origin) mix. Unfortunately for him there's three or more who are exceptional fullbacks.
"His form is good, he's certainly not out of it.
"But when you are sitting down picking a side you've got to select a balanced side.
"You've got to make a decision, but they are good headaches."
Three incumbent Maroons are already out of contention for 2008 - Dane Carlaw, Shaun Berrigan (England) and Tonie Carroll (representative retirement).
Morris said he had also been buoyed by the return of Queensland playmakers Darren Lockyer (knee) and Johnathan Thurston (shoulders) from injury in the NRL opening round.
"To see both get back on the field was great, especially the way they did it," he said.