"'Reidy' won't play. He's had an ongoing calf issue since the Gold Coast (practice) game (on March 2nd)," Buckley said at the team's recovery session at St Kilda Sea Baths on Tuesday morning.
"He hasn't passed a couple of the hurdles he's been asked to jump.
"To be conservative now, we think he's going to be another two to three weeks and we'll have to ease up his progressions."
Although the news on Reid is bleak, key forward Jesse White is over his own calf issue and will make his club debut against his former side the Sydney Swans at ANZ Stadium on Saturday night.
"He's right to go and really excited about taking on his old club," Buckley said.
"He's obviously been in the system for a long period of time and he's played the best football over his career in the last 12 months.
"He's been really focussed on taking it to another level through pre-season and he'll bring some real competitiveness in the air."
With Reid ruled out, the task of containing Swans forward Lance Franklin becomes a lot more difficult.
Nathan Brown is the man most likely to be charged with that task, although the Magpies could recall tall utility Lachie Keeffe to bolster their defensive stocks.
Keeffe was one of 14-senior listed Magpies who played at VFL level at the weekend and there were a number of players who stood out.
"We were encouraged by what we saw. Sammy Dwyer played particularly well, Jarryd Blair was up and about and Lachie Keeffe and Quinten Lynch (were impressive) in the ruck," he said.
"Fas (Alex Fasolo) was excellent off the half-back line and he's learning that role and we think it's something that's going to help develop him as a footballer."
Tyson Goldsack, Martin Clarke, Ben Kennedy, Josh Thomas and Kyle Martin also played to build up some much-needed game time.
Buckley said there were a few tough selection decisions to be made ahead of the game against the Swans.
"We're going to have a few more to select from this week which is great," he said.
"There's a few more magnets on the board than there were two weeks ago and we expect it to be that way as we build some of our players back from compromised pre-seasons."