Sinclair has arrived at the Hawthorns from Manchester City.
Clarke said: "Scott's had a full pre-season. He's in a good place, he's part of the squad here. He will play some games, he will sit some games out, he will sit some games on the bench.
"Last season was a long season for Scott without too many matches. Last weekend, going away from home, I decided it was time for the captain Chris Brunt to start the game. Chris' performance meant it was the right decision on the day.
"He will make his contribution over the season, no doubt."