Collingwood will unveil its fourth debutant of season 2011 with Ben Sinclair named as the late replacement for Dale Thomas for today's clash with Essendon at the MCG.

Sinclair will become the 1091st player to represent Collingwood since the inception of the VFL in 1897. He will start as the substitute today.

Thomas will miss the game after sustaining a corked thigh in last week's win over Gold Coast.

Sinclair, 19, was drafted by the Magpies from the Oakleigh Chargers and Scotch College with the 62nd overall pick in the 2009 Draft. He has battled a number of injury setbacks in his first 18 months with the club, but his form in recent weeks at VFL level has been exceptional.

He follows Alex Fasolo (round 12), Luke Rounds (round 15) and Lachlan Keeffe (round 16) as players to make their AFL debuts for Collingwood so far in 2011. Andrew Krakouer and Simon Buckley both debuted for the Magpies in round 1 after previously representing Richmond and Melbourne respectively.

Sinclair is a quick, aggressive midfielder who has impressed when he's played for the Magpies in NAB Cup matches in both 2010 and 2011.