Reid suffered an ankle injury last Saturday night in the win over Greater Western Sydney.
He was named in the final 22 and, privately, the Magpies are confident he will play.
Collingwood forward coach Matthew Lappin has his fingers crossed, given Reid's versatility this season.
Reid, a 2011 All-Australian defender, has played forward with great effect this season.
"I'm really excited about what he brings to our forward line," Lappin told AAP.
"He takes a helluva lot of the load off Clokey (Travis Cloke) - he's been able to have an impact when he's up there.
"Opposition defences have to pay a lot of attention to him.
"I'm really keen for him to get up, but he has to get through training on Saturday before we can say 'yes' on that one."
Reid's switch into attack was born of necessity, with the Magpies struggling to score consistently.
It is typical of a season in which Collingwood has been outstanding at times, but yet to find consistency.
While they had plenty of the ball in their forward line early against the Giants, they stunningly were 16 points down at half-time.
Collingwood only broke clear in the last term to win by 40 points.
"We were all frustrated - it's been a bit of a trend for us," Lappin said.
"We don't want to be up and down like we are, week to week, quarter to quarter.
"We still have time to fix it up."
Sunday is massive for the two teams - Collingwood is seventh and desperate to build momentum, while the Bombers need to rally quickly after Hawthorn dismantled them last Friday night.
"Essendon really did a number on us on ANZAC Day, particularly after half-time," Lappin said.
"So we take the lessons out of that ... we look to rectify that (on Sunday).
"The contest will be on - that's a given.
"It's two classic rivals, both in need of a good victory."
While the Magpies must find more potency in attack, it is the last of three priorities for the team.
First comes team defence, then winning contested ball and then scoring goals.
When Lappin was playing, the gun forwards were the centre of attention and he laughs when asked about this new order.
"If you look at our forward line, our workers are up the forward end and our Hollywood-style blokes are in the back half," Lappin said cheekily.
"That's the way footy has gone now. It's more offensive down back and more defensive up forward.
"There's still a spot for an occasional attempted mark of the year - Jamie Elliott has had a couple of goes this year."
Collingwood recalled key forward Quinten Lynch and Luke Ball, while Essendon regained captain Jobe Watson from a broken collarbone.
Veteran defender Dustin Fletcher and Kyle Hardingham also return for the Bombers and Scott Gumbleton comes in for injured key forward Michael Hurley.
