Derby County have enjoyed a fantastic season so far under Gary Rowett and currently occupy the second automatic promotion spot.

Whilst it has been a team effort from the Rams, there’s no doubt that Matej Vydra has established himself as the key man at Pride Park.

The Czech international has scored a superb 15 goals already this season, which leaves him as the joint top scorer in the entire division.

Vydra joined from Watford for a club-record fee and has shown exactly why the East Midlands side were prepared to pay £8m for his services.

But, given his excellent form and the way the market has gone, how much has he added to his value now?

We take a look…

Sam Preston

£8m has gone on his value, easily.

He is priceless to Derby right now, but considering he started the season with injury doubts and huge competition for his place, he has added more value than almost anyone else in the league. Derby cannot lose him.

Alfie Burns

The main man in Derby’s push for promotion.

Vydra has more than justified the transfer fee paid for him, and has silenced his critics emphatically.

You’d imagine that Derby value Vydra around £15m right now, but with Premier League football a possibility with him in their side, the Rams could be demanding more.

George Dagless

Around £5m.

Vydra has arguably become Derby's most important player for the way he breaks other teams down and gets goals.

There might still be questions over his Premier League suitability but he's going well this season and that's all that matters now.

Thoughts, Derby fans? Let us know in the comments below.