The Black Cats chief is being linked with a number of players, including the likes of Nelson Valdez and Stephen Ireland, and he admits he wants to add to his squad before the Premier League season begins.
Bruce spoke to Sky Sports News following Sunderland's opening pre-season friendly in Munster.
"We have got a couple of irons in the fire, we have put a bid today [Tuesday] for a player," Bruce confirmed
"I am not going to tell you who, we hope we can make inroads in it.
"I would envisage we will get a couple of new faces in before the season starts, I would have thought."
Bruce would not reveal the player's identity, saying: "You will have to wait and see."
Sunderland opened their pre-season with a win as Martyn Waghorn scored twice to see the Black Cats home 2-1, although the striker did limp off towards the end of the match with a knee injury.
"Pre-season is all about fitness and getting people ready," said Bruce.
"The one thing you want to avoid is injuries, but we did have a bit of a scare with Waghorn. But overall I am very pleased, we moved the ball better in the second-half."