Collingwood has lost a player just minutes into their blockbuster clash against the Western Bulldogs in front of a packed MCG crowd.

Reef McInnes injured his knee while contesting for a mark and the Pies defender immediately hobbled off.

Ned Long was activated as the Pies sub.

Clearly in pain, the 22-year-old could not put any weight on his right leg and needed to be helped from the ground.

McInnes headed straight down to the rooms with the club doctor.

“He was in a lot of pain, could not put any weight on it as he came from the ground,” Matthew Richardson said in commentary on Channel 7.

It was revealed in the second half Collingwood medical staff fear McInnes had suffered an ACL injury, which if confirmed by scans would be season ending.

The injury came shortly after Sam Darcy kicked the Dogs’ first goal after Collingwood captain Darcy Moore was pinned for holding the ball.

The Bulldogs, who reverted to their original club name of Footscray to mark their 100th year tonight, were on top early going to the first break ahead 22-16.

Laitham Vandermeer and Lachlan McNeil kicked the Dogs’ other two goals, while Lachie Schultz and Daniel McStay booted the Pies’ two majors.

Nick Daicos racked up 11 touches, while Scott Pendlebury had eight in the first quarter.

Pendlebury also suffered a slight knock to the head while ducking down to get the ball and went to the dressing room after coming off but was back on the field for the second quarter.

Collingwood came at the Bulldogs and took the lead in the second quarter but Footscray kicked three goals to the Pies’ two to lead 43-38 at halftime.

Darcy was proving hard to handle for Moore as he kicked two of the Dogs’ second quarter goals. He had 10 disposals, five marks and seven kicks at the main break.

The Pies butchered some late chances to the lead with Daniel McStay kicking a point infront of an open goal less than 30 metres out.

Tom Liberatore was everywhere for the Bulldogs with 18 touches, while Daicos had 17 at halftime.

With 7NEWS