The Sharks lost Fifita barely seven minutes into their Magic Round win over the Titans and Prior not long after.
But veteran skipper Paul Gallen lifted in the pair's absence along with big contributions from bench forwards Brayden Hamlin-Uele, Jack Williams and Jayson Bukuya to overturn an 18-10 halftime deficit to run home 26-18 winners over an ill-disciplined Gold Coast at Suncorp Stadium on Thursday night.
"We're getting used to playing without that talent at the moment but I wouldn't have thought we'd have lost both my starting front-rowers, but they keep finding a way," Morris said.
"Andrew's had a minor hamstring complaint a couple of weeks ago, I think it's something similar but they don't think it's too serious which is good.
"Matt has had a few burners with his neck or shoulder, he had one last week in the first tackle of the game. He came out of the first tackle [tonight] with a bit of an issue but it's more localised in his neck at the moment and they didn't want to risk him.
"They don't think it's too serious, we have a long turnaround so hopefully they'll both be OK."
The Sharks now have a 10-day break before hosting the Sea Eagles at PointsBet Stadium on May 19.
The Titans win was Gallen's final match at Suncorp Stadium (unless Brisbane earn an unlikely home final against the Sharks) and he finished it with a match-sealing try and conversion, with his coach praising the veteran's efforts.
"He played the first 50 metres straight and his stats read 200 metres gained, a try and - I didn't think I'd say this but - a goal," Morris said smiling.
"What a way to go out at Suncorp Stadium for the big fella."
NRL.com Stats has Gallen making 23 runs for 200 metres, 76 post-contact metres, four tackle-busts, a line-break and 27 tackles, along with his try and conversion. That underlies - in the absence of the other senior middle forwards - the skipper's contribution was crucial to the win.