The unbeaten Storm are heading to Newcastle to take on the Knights, who will be desperate to crack their first win of the season after a golden-point defeat in Townsville last round.
They are without injured Munster for the third straight match as well as his suspended partner Jahrome Hughes, with Jonah Pezet and Tyran Wishart the new halves pairing.
Newcastle will also start with former Panther Jack Cogger in the No.7 jumper at McDonald Jones Stadium, relegating Jackson Hastings to the bench.
Ex-Melbourne skipper Cameron Smith revealed this week that the Storm hadn't been able to fully diagnose Munster's injury and Bellamy did little to allay concerns following their final training run on Saturday.
"He looks like he's improved this week but it's been stated before, he's been up and down," Bellamy said.
"He looks like he's really getting better and then all of a sudden he turns back again.
"I think he's been a little bit more consistent this week so hopefully he's a bit closer to playing than he was this time last week."
Pezet has played at five-eighth in Melbourne's two wins over Penrith and the Warriors, while it's utility Wishart's first start of the season.
Tyran Wishart sneaks through a gap in the Roosters' defensive line. (Rob Prezioso/AAP PHOTOS)
Bellamy was satisfied with their preparation, despite the late decision not to appeal Hughes's ban for his referee push.
"We haven't had a whole heap of time this week as we had a couple of training sessions before we knew what we were going to do with Jahrome, but Jonah has been in there for all of the games and Wish (Wishart) has played a little bit of halves with us," the veteran coach said.
"In the limited time this week they've done a good job so hopefully that will continue on Sunday night."
Bellamy said that while it was the first start this season for Cogger, who began his career with Newcastle, he was an accomplished halfback.
"He's a really experienced player and he's played in the grand final for the Panthers last year and done a really good job," Bellamy added.
"He's mainly been coming on a dummy-half but he's a very accomplished player and we know he's going to do a good job for them."
Melbourne escaped with a miraculous victory over the Warriors thanks to the aerial skills of winger Xavier Coates, who scored in the final seconds.
Bellamy said a takeaway from the match was how they let an ample lead slip to put themselves in such a position.
"The Warriors are a good side but our 12-point lead got eroded slowly but surely and they really pinned us in our half and to be quite honest we did well to get out of it," he said.
"That's an area we will be looking to get a bit better at this week."
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