Douglas has said that he has to be ready for action if Leeds head coach Marcelo Bielsa wants him to start.
The left-back had injury issues last season, and when he recovered his fitness and was available for selection, he could not displace Stuart Dallas from the starting lineup.
Dallas is a winger by trade, but the Northern Ireland international has done well at left-back for Leeds.
The Daily Mail has reported of interest in the 30-year-old left-back from Celtic, with the report adding that the Hoops have already held talks with Leeds over a transfer for the Scotland international.
Douglas told The Yorkshire Evening Post: “The manager makes the decisions at the end of the day. I need to live by that. It can be frustrating at times but it’s a team game and it’s not all about me.
“I just need to be ready when I get the opportunity and I think I showed I was ready [last season] and helped the team when I could.
“It was nice to contribute but ultimately I want to play more like every player, so it’s going to be challenging ahead for everyone to be on their toes and be at their best.”
Celtic transfer from Leeds United?
Douglas is a very good left-back who has a lot of experience, and he would be a good signing for Celtic.
With the left-back not guaranteed a place in the starting lineup at Elland Road, a move to Celtic Park could be appealing to him.