The 26-year-old striker was forced to sit out the Black Cats' 2-0 defeat to Benfica on Wednesday, as they brought the curtain down on their pre-season tour of Portugal.
His absence sparked speculation that he was facing up to a lengthy spell on the sidelines.
That would be the last thing Sunderland need, as they rely heavily on Bent to provide them with a cutting edge.
He scored 25 goals in all competitions for the club last season, providing an instant return on the £10million it cost to lure him away from Tottenham.
Had he been forced to miss the start of the 2010/11 campaign, the Black Cats would have been lacking an attacking spark.
Bruce, though, is adamant that Bent was rested against Benfica as a precaution and is confident he will be ready to face Birmingham in their Premier League opener on 14th August.
"Darren's fine, but he's got a couple of minor niggles and it wasn't worth risking him," he said in the Sunderland Echo.
"The situation did at least allow us to experiment with a 4-5-1 formation and explore that.
"It was a good game and it has been a good trip."
Bruce also revealed that a slight knock picked up by his other leading marksman, Kenwyne Jones, is nothing to worry about.
He added: "He's twisted his knee a little, but he'll be fine."