Darcy was initially told he had probably torn the anterior cruciate ligament in his left knee when he landed awkwardly in the Bulldogs' win over St Kilda in round six.
It was then thought the 21-year-old would require surgery and face a lengthy stint on the sidelines.
But he ultimately avoided the need for surgery and missed only six games with an impaction fracture and associated ligament damage.
Bulldogs coach Luke Beveridge confirmed Darcy will return to action in another clash with the Saints at Marvel Stadium on Thursday night.
"He's done a really scrupulous and professional job on rehabilitation from that injury," Beveridge said on Wednesday.
"We welcome him back and look forward to having him part of tomorrow night."
Darcy enjoyed a hot start to the year, kicking 14 goals in his first five games.
The 205cm aerial threat will add to the free-scoring Bulldogs' attacking weapons against St Kilda as they look to bounce back from a humbling last-start defeat to Hawthorn.
"We'll blend a little bit of ruck time in there to make sure he's involved in the game," Beveridge said.
"But he's an enormous threat (in the forward line) and we saw the way that his early part of the season was evolving and his presence.
"Early in the game last week, Hawthorn took a lot of intercept marks. With Sam there (against St Kilda), that definitely won't happen."
Darcy and fourth-gamer Cooper Hynes replace Ryan Gardner (omitted) and James Harmes (concussion) in the Bulldogs' side.
St Kilda have regained former Dogs midfielder Jack Macrae (lung) and Liam Stocker (foot) from injuries, while Mattaes Phillipou (calf) and Hugh Boxshall (omitted) are out.
Darcy's return is a further boost for the Bulldogs after confirmation Beveridge had agreed to a two-year contract extension, tying him to the club until 2027.
The Bulldogs' longest-serving coach, who led the club to the 2016 premiership, is hopeful out-of-contract captain Marcus Bontempelli will soon follow suit.
"It's important for all of us," Beveridge said.
"What an incredible player Marcus has been, and what a citizen and person he is.
"I haven't got a line of sight on it, I don't know the detail, but I know (Bontempelli's manager) Tom Petroro and (Bulldogs list boss) Sam Power are always talking.
"Hopefully over the next couple of weeks there'll be some news on that."
The Bulldogs (6-6) will start warm favourites against St Kilda (5-7), despite Ross Lyon's side enjoying a surprise last-start victory over Melbourne before their mid-season bye.
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