Bent was forced to withdraw from England's European Championships qualifier with Montenegro after injuring his groin in training yesterday morning.
The striker had been expected to make his first competitive international start at Wembley tonight after breaking his England duck as a second- half substitute in last month's 3-1 win in Switzerland.
However, yesterday's setback, in which Bent pulled up during a routine training drill, means Fabio Capello will now pair Peter Crouch with Wayne Rooney as England look to maintain their 100 per cent record against a Montenegro side that have emerged as the surprise packages in Group G.
While the rest of the squad returned to their team hotel for a series of tactical discussions yesterday afternoon, Bent was accompanied by England's medical staff as he underwent a scan on his injured groin.
The full extent of the injury will not be apparent until later today, but Sunderland officials are hoping it is a relatively minor problem rather than a fully-blown tear.
With the Black Cats' weekend game at Ewood Park having been put back to Monday to accommodate live television coverage, the striker has an extra 48 hours in which to recover, and Steve Bruce will be hoping he is given the green light to return to training at the end of the week.
Either way, yesterday's injury will have come as a major blow to Bent, who has suffered a succession of problems during his recent stints on international duty.
A hamstring injury forced his withdrawal from May's friendly with Mexico, and may have played a part in his subsequent failure to make the 23-man squad for the World Cup finals, while a back problem ruled him out of August's friendly with Hungary.
Capello still appeared sceptical about Bent's qualities at that stage, but having described the 26-year-old as one of the most important players for the future last week, the England boss was ready to hand him a starting berth before he was forced to change his plans yesterday afternoon.
Bent is not fit, confirmed Capello. He will not play. He felt some little pain (in the groin).
It is hard on him after scoring the goal against Switzerland but this is the situation and I will play Crouch.
Unsurprisingly, Bent was extremely frustrated at his latest setback, and the Sunderland striker immediately updated his Twitter account with: Devastated, gutted, upset, angry all words that sum up this situation.
Bent's absence has piled further pressure on Rooney's shoulders as he prepares to lead the England attack despite a poor start to the season at club level.
Rooney has been struggling with injury problems of his own he sat out Manchester United's goalless draw at the Stadium of Light ten days ago because of an ankle problem and has struggled to come to terms with the various allegations that have affected his private life.
He has failed to score from open play for his club side, but impressed in last month's two international outings against Bulgaria and Switzerland, scoring England's opener in Basle.
He remains Capello's talisman, and the Italian insists he has no concerns about Rooney's mental or physical state.
Rooney will play, said the England boss. He is feeling good. I spoke with Wayne and he told me his ankle is okay.
He trained fantastically and without pain.
He is in a good moment. I spoke with him about different things and he is happy.
Rooney is expected to play in a withdrawn role this evening, enabling him to float between the England midfield and target man Crouch.
With Rop Ferdinand to line up alongside Joleon Lescott in the absence of the injured John Terry and Phil Jagielka, Capello's biggest selection dilemma comes in midfield.
Steven Gerrard will partner Gareth Barry in the middle of the park, with former Middlesbrough winger Adam Johnson expected to line up on the left-hand side. That leaves a straight choice between Ashley Young, Shaun Wright-Phillips and Stewart Downing for the wide berth on the opposite flank.