Derby boss Frank Lampard is set to be without one of his key men on Saturday, as his side face off against Aston Villa, who will certainly provide Lampard's side with a difficult test. 

Mason Mount has been in excellent form for the Rams this season but picked up an injury during their defeat to his parent club, Chelsea in the EFL Cup.

The creative midfielder sat out their win over Birmingham at the weekend, but is still yet to recover from the injury and will be a huge miss for Lampard's side in this weekends game.

Lampard is already without central midfielders George Evans and Craig Bryson and it leaves him with a lack of options in midfield, but youngster Duane Holmes is likely to start after impressing in the win over Birmingham last weekend.

Martyn Waghorn is a major doubt after he was forced off with a hamstring injury against the Blues, and faces a race in time to be fit for this one.

In contrast, Dean Smith has a nearly fully-fit squad to choose from for the game against the Rams, with a key midfielder being welcomed back to a return to action.

Birkir Bjarnason has returned to the squad after recovering from a groin problem that saw him miss the win over Bolton in the previous weekend.

Albert Adomah is expected to retain his place in the starting XI after recovering from a knee problem, but youngster Keinan Davis isn't expected to return to the side for another two weeks after a hip operation.

The Verdict: 

The news of Mason Mount's absence is a huge blow to Frank Lampard and they face a tough task against an Aston Villa side who will be in search of their first away points under Dean Smith this season.

But with Birkir Bjarnason returning to the side for Villa, they may have the edge coming into Saturday's game, which will be a huge boost to Dean Smith.

Derby are in an excellent run of form but their defence will be tested against an Aston Villa side that has some of the best attacking talent at their disposal.