The former Middlesbrough winger confirmed: "The first thing I asked the manager was 'are these players staying? Because I would like to play with them' and his response was 'no players will be leaving this football club unless they're not playing.
"He said the likes of Ashley Young will not be leaving because he is trying to build a squad, not dismantle one. That was great news for me and that's what made me sign really."
Downing added: "I've known Ashley for quite a few years, I've seen him come here from Watford and he's done really well.
"There's no rivalry. I might play on the left, him on the right, it might be the other way around. He might play up front, I might play up front. You need options, you have 60 odd games to play over the season.
"The manager here didn't use many players last season.
"You need competition at a top club and this will bring the best out of everyone."