Brentford are reportedly concerned that Ben Mee will miss the rest of the season with a foot injury.
Mee made his seventh consecutive Premier League start in Monday's 4-2 defeat to West Ham United at the London Stadium.
However, the 34-year-old was unable to complete the game after being forced off in the 61st minute due to an injury issue.
According to the Evening Standard, scans have indicated the Brentford centre-back could be out of action for an extended period.
As a result, the Bees are fearful that they may have to play out the remainder of the campaign without one of their key defenders.
The loss of Mee represents a significant setback in Brentford's fight to extend their top-flight stay into a fourth consecutive season.
Mee has started 13 of Brentford's last 15 Premier League matches, and he only missed December's games against Wolverhampton Wanderers and Crystal Palace due to suspension.
Thomas Frank is already having to cope without a number of absentees, including Mee's fellow central defender Ethan Pinnock.
The 30-year-old has been ruled out until the international break after picking up an ankle injury in the 2-0 win over Wolverhampton Wanderers earlier this month.
Mee and Pinnock's injuries leave Frank with just three fit centre-backs – Kristoffer Ajer, Nathan Collins and Zanka.
The Brentford head coach is also unable to call upon Josh Dasilva, Rico Henry, Aaron Hickey, Kevin Schade and Bryan Mbeumo.
Having picked up 25 points from 26 matches, the Bees are languishing in 16th place and five points above the bottom three ahead of the weekend's round of fixtures.
Brentford will be hoping to extend that gap when they welcome fellow West London side Chelsea to the Gtech Community Stadium for Saturday's Premier League contest.
