There was a certain atmosphere of sadness in the air as Villa took the field against Wigan last Saturday - sadness because, in 90 minutes time, Villa would be saying farewell to a top-class striker for the remainder of the season.

What wasn't known, as the teams lined up at the DW Stadium, was that, come 5pm or thereabouts, Villa would be facing the reality of losing a second forward player of undoubted quality.

Saturday was all about Robbie Keane, and his final appearance of a pretty impressive short-term loan spell from LA Galaxy: three league goals, two of them coming in Villa's last league win, at Wolves, and no end of deft touches, examples of quick-thinking vision, reminders that, in all probability, here is a player still well worth a regular role with a Premier League club.

More than a hint of regret, certainly, that Keane took the decision last summer to pack his passport and head for the MLS. More than a hint of regret that Villa were unable to extend his temporary visit from Los Angeles. We'd seen enough of Keane, in six weeks, to know his loss would be felt.

Regret over Keane later gave way to another emotion: distress and concern over Darren Bent. Bent, the player whose goals last season were chiefly the reason for firing Villa away from the bottom reaches of the Premier League and eventually to ninth place, was stretchered off midway through the second half after twisting awkwardly on his ankle. His pain was obvious, and first impressions - that this was an injury of significance - proved correct.

Ruptured ankle ligaments has been reported; at the time of writing it hasn't yet been established whether Bent will require surgery or not. But whether the diagnosis is as serious as ligaments being ruptured or not, his recovery time has been put at 12 weeks. That comfortably rules him out for the rest of the season, almost certainly England's Euro 2012 campaign too - a particular blow to Bent personally, who was surely set to lead England's line in the absence of Wayne Rooney.

And so, Villa went into the game at Wigan with two leading strikers, and finished without them. In the case of Bent, this is the worst possible point of the season to be without him. While it's not unfair to suggest he's been slightly below his best this season, and definitely not in the same blistering form he showed in his first few months as a Villa player, Bent's contribution cannot be underestimated. He's scored ten goals in 25 appearances for Villa this season, nine in 22 Premier League matches. Important goals too - when Bent has scored, Villa have tended to be productive.

Six of those league goals have come in five of Villa's six Premier League wins this season. Bent scored against Blackburn (home win), Wigan (home win) and twice against Norwich (home win), as well as Chelsea at Stamford Bridge on New Year's Eve (away win) and at Wolves towards the end of January (away win and Villa's last league victory). Two of his other league goals were point-savers, helping Villa to claim draws at home to Everton and QPR.

Vital goals, especially given the context of what is becoming a desperate season. Who have Villa got who can replace Bent and supplement those goals? The options are rather thin on the ground.

For clues as to a Villa team without Bent, we don't have to look too far. For a period in December, the team were without him as he nursed a minor injury; indeed, the most impressive result of the league season, the 3-1 win at Chelsea, came without him in the starting line-up - although he did enter the fray late on to claim the third, and then underlined his importance to the side by hitting four in four in Jan/Feb; Everton, Wolves, Arsenal (FA Cup) and QPR.

Against Blackburn this weekend, I'd expect - and hope - Villa to revert to the shape they used at Chelsea. I've felt, all season, that it's the formation that suits the current squad best (albeit with Bent as the centre-forward). It requires a three-man midfield, with one player playing further forward than the other two. With Ciaran Clark also sidelined with injury, I'd pair fit-again duo Petrov and Herd together in the 'engine room' and play Stephen Ireland - so effective towards the end of 2011 and beginning of 2012 - in a more attacking role.

The front three would be Mark Albrighton on the right and Charles N'Zogbia on the left (again, like Ireland, a player dropped just as he was beginning to show some form), with Gabby Agbonlahor as the striker through the middle, reprising the lone centre-forward role he's excelled in on previous occasions. This leaves Emile Heskey, Andreas Weimann and possibly Nathan Delfouneso as striking options on the bench, either to relieve Agbonlahor, or - more likely - to support him if Villa need a second striker later in the game.

Villa cannot replace Darren Bent. But they must adjust to life without him and there is the opportunity now for Alex McLeish to console himself with a formation and line-up which I believe will suit every player (certainly every player in the front six) in the team I have just suggested. No square pegs in round holes with this one.