Following Everton's £30m bid for Sunderland keeper Jordan Pickford, how much do you think QPR stopper Alex Smithies is worth?

With the news that Everton are on the verge of signing Sunderland goalkeeper for the huge sum of £30m, it's left every football fan wondering how valuations have become so distorted.

Granted, Pickford was one of Sunderland's only players to come out of last season with any credit whatsoever, and given his age and his growing reputation in the game, £30m may not actually be a bad fee if the Toffees can get a few years service out of him before potentially selling him on.

The 23-year-old, has only played one full season in the Premier League, but has experienced first team football in each of the last five seasons as he has worked his way up the footballing pyramid via Darlington, Alfreton Town, Burton Albion, Carlisle United, Bradford City and Preston.

Which begs the question, how much could QPR goalkeeper Alex Smithies be worth in 12 months time?

Smithies has already established himself as one of the best goalkeepers in the Championship, and has been linked with a number of Premier League teams already this summer.

Whether this move materialises remains to be seen, but what we've seen in Pickford is how just one successful season in the top flight can increase your value infinitely.

It's likely that should the 27-year-old move to the Premier League this summer, it would be for a fee in the region of £8m, yet if he was to be a success at that level his value could sky-rocket to around the £20m mark with his best years still very much ahead of him.

The same can be said for players such as Burnley's Michael Keane, and Middlesbrough's Ben Gibson, who despite limited experience in the top-flight, have seen their values boosted through proving their ability to perform regularly at that level.

The nature of the market only goes to show the importance of sell-on clauses in the modern day, as the transfer market for young English players can be extremely fruitful for the selling club, hence why negotiations can sometimes be so drawn out, as both clubs look at the most minor of details which could potentially have a huge impact in just a small amount of time.