Dawes suffered a knee injury in the Magpies' semi-final triumph over West Coast last Saturday and had to hobble through the final term as Collingwood had already subbed Didak out with a calf problem.
While Didak has not recovered in time for Friday night's preliminary final against the Swans at ANZ Stadium, Dawes has been picked with the 24-year-old big forward and second ruck option crucial to Nathan Buckley's Collingwood set-up.
Sinclair returns immediately for Collingwood having played in the Magpies' 38-point qualifying final defeat to Hawthorn.
Sydney have brought Heath Grundy straight back into their side after the 26-year-old defender served his one-match suspension for striking Geelong's James Podsiadly in the Swans' Round 23 clash with the Cats.
In Saturday's twilight preliminary final between Hawthorn and Adelaide, Crows coach Brenton Sanderson has selected Jared Petrenko despite the 22-year-old finishing last Friday's semi-final win over Fremantle in tears after dislocating his right shoulder just before the final siren.
But after undergoing a tackling fitness test behind closed doors, Petrenko has seemingly proven his fitness for Adelaide's trip to the MCG.
Sanderson has picked Andy Otten as a defensive replacement for Sam Shaw, who was subbed off with a hamstring injury against the Dockers.
Hawthorn have brought Jordan Lewis and Clinton Young back into the side with the two left-footers having recovered from minor hamstring and calf injuries respectively.Lewis and Young have replaced Brendan Whitecross, who suffered a season-ending knee injury against Collingwood a fortnight ago, and the omitted Thomas Murphy.