West Bromwich Albion goalkeeper Sam Johnstone has been the subject of heavy transfer speculation ever since the Baggies were relegated from the Premier League.

Despite this, the Hawthorns club were able to keep hold of Johnstone last summer, and the 28-year-old has gone on to feature 31 times for the club so far this campaign.

However, Johnson's contract is due to expire this summer, and according to a report in The Sun, Manchester United have now joined the list of clubs lining up a summer move for the goalkeeper.

The Sun also states that West Ham are the ones leading the race for the Englishman's free signature, with Tottenham Hotspur and Southampton also interested in making a deal.

With that being said, here, we take a look at some of Sam Johnstone's numbers this season on WyScout, assessing what he does well, and where he could improve.

First of all, let's take a look at Sam Johnstone's expected goals conceded (xGC).

In the Championship this season, Johnstone has underperformed by the smallest of margins when it comes xGC, conceding 0.8 goals per 90, with an xGC per 90 of 0.79. A 0.01 discrepancy.

This is neither good nor bad, but, Manchester United number 1 goalkeeper David de Gea, whom Johnstone would be in competition with at Old Trafford, has overperformed his xGC in the Premier League this season, conceding more goals per 90 at 1.27, but doing so with an xGC of 1.58 per 90.

Sam Johnstone's save percentage is also lower than that of David de Gea's at Manchester United.

Johnstone faces 2.5 shots per 90, saving 68 percent of these, whereas de Gea faces 4.67 per 90, saving 72.8% of the shots he faces.

This is only a marginal difference, but again demonstrates the level of competition Johnstone would face at Manchester United if he wanted to fight for the number one shirt.

Finally, distribution is a key factor for goalkeepers in top teams nowadays, so lets look at the numbers in this area.

Sam Johnstone takes 1.67 short kicks per 90 and 4.02 long kicks per 90. This doesn't necessarily mean that Johnstone cannot take short kicks, but he does favour longer ones, although, this could be what is being asked of him by the manager.

David de Gea takes 3.33 short kicks and 4.1 long kicks per 90, for example, with short kicks taking up a much higher percentage of his overall kicks.

This shows Johnstone would be required to change his approach when taking goal kicks if he was to make the move to Manchester United.

All in all, Sam Johnstone would be a good pick up for Manchester United if they viewed him as a number two, however, he would face tough competition in David de Gea for the number one jersey.

Johnstone's numbers are not shabby, but he would be up against a truly world-class operator in de Gea for the starting spot at United and on the evidence of these numbers, de Gea would hold off his challenge.

As de Gea's deputy though, this could be a very shrewd signing from United this summer, if they can beat the host of other clubs interested to his signature.