MORE: Victory grind out win over Roar
The fullback pulled a muscle and was forced off 17 minutes into a 1-0 loss to Melbourne Victory on Friday, a game the visitors fought hard in before conceding an own goal with 13 minutes remaining to leave empty handed.
Veteran defender Stefanutto will now join Jack Hingert, Michael Theo and Adam Sarota on the sidelines.
Jean Carlos Solorzano should return next week after missing the Victory loss due to a shoulder problem.
But with the absence of departed duo Besart Berisha and Ivan Franjic being keenly felt in 2014-15, Mulvey knows reinforcements are required at Suncorp Stadium, particularly having allowed Liam Miller to walk away from the club following a disagreement between the player and his coach.
"The salary cap can hurt you," he said.
"What we're doing is we're bedding new players into our system. But the A-League is growing. The quality of players coming into the league is growing. You can't stay at the top all the time. But I've still got every faith in this group.
"We need to strengthen a little bit. We need to look at the situation with Shane, he's probably out for five or six weeks now. Jack Hingert's out for five or six weeks. We need to replace Liam Miller as well. We need to do some work in that area."
Despite being undermanned and up against it, Mulvey insisted the Roar are not making up the numbers in 2014-15.
"I still think we can have a big say in what goes on this year. Last week we turned the corner, definitively," he said, referring to a 4-0 win away to the Newcastle Jets.
"Tonight we've come up against one of the team (that's) everybody's favourites. We were pretty much equal apart from an own goal. Sometimes when you're down the bottom, these things go in."
The fullback pulled a muscle and was forced off 17 minutes into a 1-0 loss to Melbourne Victory on Friday, a game the visitors fought hard in before conceding an own goal with 13 minutes remaining to leave empty handed.
Veteran defender Stefanutto will now join Jack Hingert, Michael Theo and Adam Sarota on the sidelines.
Jean Carlos Solorzano should return next week after missing the Victory loss due to a shoulder problem.
But with the absence of departed duo Besart Berisha and Ivan Franjic being keenly felt in 2014-15, Mulvey knows reinforcements are required at Suncorp Stadium, particularly having allowed Liam Miller to walk away from the club following a disagreement between the player and his coach.
"The salary cap can hurt you," he said.
"What we're doing is we're bedding new players into our system. But the A-League is growing. The quality of players coming into the league is growing. You can't stay at the top all the time. But I've still got every faith in this group.
"We need to strengthen a little bit. We need to look at the situation with Shane, he's probably out for five or six weeks now. Jack Hingert's out for five or six weeks. We need to replace Liam Miller as well. We need to do some work in that area."
Despite being undermanned and up against it, Mulvey insisted the Roar are not making up the numbers in 2014-15.
"I still think we can have a big say in what goes on this year. Last week we turned the corner, definitively," he said, referring to a 4-0 win away to the Newcastle Jets.
"Tonight we've come up against one of the team (that's) everybody's favourites. We were pretty much equal apart from an own goal. Sometimes when you're down the bottom, these things go in."