The Tigers coach was adamant the news that captain Jarome Luai will leave for the PNG Chiefs in 2028 was not to blame for a performance at Shark Park on Sunday that Marshall branded "unacceptable".
Luai's signing with the NRL's 19th franchise dominated headlines last week, but the five-eighth struggled to put his stamp on the game once Doueihi went off after 10 minutes with a shoulder issue.
The Tigers, without Doueihi, first-choice hooker Api Koroisau and fullback Jahream Bula, trailed 18-10 at halftime but failed to score a second-half point as Teig Wilton and KL Iro grabbed hat-tricks for the Sharks (4-4).
"I thought we got taught a lesson by a classy side tonight on how to run hard and how to tackle hard, how to win the field position and apply pressure - and we got dominated," Marshall said.
"I thought we tried to play soft to try and win - you actually have to play physically.
"I can't accept things that revolve around effort. Footy mistakes I can accept, but effort, no.
"We've had things that have been distractions all year, so it (Luai's contract call) is no excuse."
Wilton opened the scoring for Cronulla on Sunday before Doueihi crossed in the 10th minute and dislocated his shoulder in the act of scoring, leaving his hopes of a NSW Origin debut hanging by a thread.
Doueihi was floated as a perfect bench utility for Laurie Daley because of his versatility.
The Blues coach had seen Mark Nawaqanitawase, Angus Crichton and Kotoni Staggs join Payne Haas, Tom Trbojevic and Api Koroisau this weekend on his list of players unavailable for the series opener on May 27.
"The shoulder dislocated and they put it back in," Marshall said of Doueihi.
"He'll get a scan tomorrow. I'm unsure of the time, but maybe it's four to six weeks."
Fainu was carried off with five minutes remaining and left the ground in a moon boot.
Taylan May followed Doueihi over the tryline in the 15th minute, but that was the last time the Tigers would breach the Sharks' defence.
Iro and Jesse Colquhoun hit back to put Cronulla up at the break, and from there Craig Fitzgibbon's side never took their foot off the gas.
Wilton and Iro brought up hat-tricks, while Nicho Hynes and Sam Stonestreet also crossed as the Tigers were starved of the ball and completed at just 58 per cent in the second half.
Rookie winger Faaletino Tavana had a particularly tough game under the high ball, making five errors in a forgettable night that leaves the Tigers 5-3 to start the season.
Fitzgibbon was buoyed by his side's response after questioning their attitude in last week's loss to North Queensland.
"It's a long week when you perform like last week," he said.
"We played like the team we want to be today. It's a moment in time. You don't become something over 80 minutes, but it's a good start."