Brentford boss Thomas Frank has confirmed Bryan Mbeumo is set for a spell on the sidelines with a "bad" ankle injury.

The Cameroon international picked up an injury in Wednesday's 2-1 defeat to Brighton & Hove Albion at the Amex Stadium.

Mbeumo, who opened the scoring from the penalty spot, was forced off in the 40th minute after he rolled his ankle in an attempt to defend against Pascal Gross.

Speaking ahead of Saturday's away meeting with Sheffield United, Frank revealed that Mbeumo will be out for "weeks".

"It is bad," Frank told reporters at Thursday's press conference. "He'll have a scan later, but we don't know the exact number of weeks he will be out.

"He will definitely not play on Saturday, and he will be out for weeks. We will know more in the next couple of days.

"[Bryan] must be number two after Ivan Toney in terms of goals and assists, which is key. His work rate for the team is incredible; you don't see many wingers who work so hard and mean so much.

"He's become the key man - 'give me the ball, I'll take this'. Who will that man be now? We'll find out in the next weeks."

Mbeumo is Brentford's top scorer this season with seven Premier League goals, helping fill the void left by Toney, who is serving an eight-month betting ban.

Unfortunately for the Bees, the forward has been added to a lengthy injury list, which includes Rico Henry, Kristoffer Ajer, Aaron Hickey, Josh Dasilva, Nathan Collins and Kevin Schade.

Despite having to contend with a number of injuries, Frank is trying to remain "positive" ahead of Saturday's trip to Bramall Lane.

"Football is such a marginal game," the Brentford boss added. "Inside of the post, outside of the post, deflection - there are so many things that you can't control.

"And another thing is injuries. We need to do everything we can to recover well, assess and get players back, but there's also just bad luck in it. Bryan's injury is a clear one - it's bad luck. He got caught, got pushed and rolled his ankle. It's very frustrating, but I'm a positive guy and we'll find a solution."

Brentford were provided with a much-needed boost in midweek after Mikkel Damsgaard returned from injury to play the final 20 minutes against the Seagulls.

Frank has also stated that a late decision will be made on Mathias Jensen's availability for Saturday's contest, with the midfielder closing in on a return to action following a three-game injury absence.