The 19-year-old injured his ankle during this month's 1-1 draw with Wigan, but the extent of the problem was difficult to ascertain while his foot remained swollen.
Scans have ruled out the need for surgery, but confirmed significant damage to Henderson's ankle ligaments.
As a result, the midfielder will be sidelined for around a month-and-a-half, ruling him out of up to six more matches.
Obviously, we're glad there's no serious damage,
said Bruce. But to be without a player like Jordan for six weeks is a blow.
We can now get on with the rehabilitation process. Jordan is keeping his spirits up and he is prepared to work hard while he is out.
Bruce is facing a midfield headache ahead of Saturday's game at Arsenal, as Henderson will be joined on the sidelines by suspended duo Lee Cattermole and David Meyler.
The pair were both dismissed in this month's draw at Portsmouth, and with Andy Reid also ruled out of this weekend's match because of a hamstring injury, Bruce will be hoping Steed Malbranque is given the green light to travel to London.
Kieran Richardson and Fraizer Campbell are back in full training and available for the trip to the Emirates Stadium, but Malbranque is still recovering from the muscular problem that led to him being rushed to hospital after complaining of chest pain at Fratton Park.
Meanwhile, loanee Martyn Waghorn has opened the door on a permanent move to Leicester by admitting he will be happy if the Foxes make a bid for his services this summer.
Waghorn has scored six goals in 28 appearances since joining Leicester on loan last August. He will remain at the Walker's Stadium until the end of the current campaign, and Leicester boss Nigel Pearson is expected to launch an attempt to sign him permanently in the summer.
Steve Bruce is likely to rebuff Pearson's advances, but having made just two Premier League starts for Sunderland prior to joining the Foxes, Waghorn will be disappointed if he is forced to return to Wearside in order to sit on the bench.
We will see what happens at Leicester, said the South Shields-born striker. I am enjoying my time at Leicester, but I've been at Sunderland for ten years, since I was a lad.
I love Sunderland as a place and would be happy to go back, but I would also be happy at Leicester.
I am enjoying my role as the lead striker, but we will have to see what happens in the summer. I will take it as it comes, but I want to play football.
Wherever it is, I will do my best.