WITH Allan McGregor seemingly on the verge of retirement, Rangers manager Giovanni van Bronckhorst will likely be on the lookout for a new No.1 at Ibrox this summer.
The rumour mill has been in overdrive and a number of goalkeepers have been linked with a move to Govan to take the reins from McGregor, who appeared to be waving farewell to supporters after being brought on for the final few minutes of his team's Scottish Cup triumph.
Keepers from Scotland and further afield are said to be on the Glasgow club's shortlist, while some supporters have called for back-up goalie Jon McLaughlin to be given a run in the team as first pick between the sticks.
Here, we take a look at the options that Van Bronckhorst has available to him and the players that have been linked with a move to Ibrox in a bid to see which goalkeeper would be the best fit at Rangers.
In order to do this, we will examine how many goals a keeper conceded per game and compare that to their expected goals against (xGA), with the difference between the two figures showing how much each player was over or under-performing.
Allan McGregor
The veteran goalkeeper looks set to hang up his gloves and although he remains a cult hero at Ibrox, it is perhaps time that Rangers should be looking for a successor.
McGregor conceded 0.81 goals per 90 minutes in the Premiership last season and had an xGA per 90 of 0.82, leaving a differential of +0.01. In a nutshell, this means that McGregor performed roughly as well as he should have, based on the quantity and quality of shots he faced.
For a team with title pretensions, however, it is reasonable for the club to aim a little higher. McGregor's performance is not an area of huge concern but there is no getting away from the fact that a better option could well be out there.
Jon McLaughlin
McGregor's understudy has provided a safe pair of hands whenever called upon this season and that has naturally led some supporters to call for a run in the team for the Scotland internationalist.
However, those shouts could be a little hasty. We have a small sample size when examining McLaughlin's statistics so the usual caveats apply, but the data suggests that the 34-year-old has slightly underperformed this term.
McLaughlin shipped just 0.43 goals per game this season - a remarkably low tally, but it must be pointed out that he was generally playing in games where Rangers were huge favourites - but the former Hearts keeper has an xGA per 90 of 0.37.
This means that McLaughlin was conceding 0.06 goals per game that he really should have been stopping, based on probability. That might not sound like a lot but over the course of a 60-game season, the discrepancies add up.
Benjamin Siegrist
The Dundee United shot-stopper is out of contract this summer and looks set to depart Tannadice after four successful years on Tayside.
Statistically, the Swiss has been a stand-out performer since United sealed their return to the Premiership and this season has been no different. Siegrist let in 1.14 goals per game this term but with an xGA of 1.31, meaning he was significantly overperforming.
Siegrist prevented 0.17 goals per game this year - which works out at a goal every six games - and this is one of the highest tallies for any player in the top flight. The fact that he has produced similar numbers in previous campaigns demonstrates that this season is no outlier, and the 30-year-old can be relied upon to outperform his xGA.
Zander Clark
Another player who is available on a free transfer and another who has been linked with a move to Ibrox for some time. The St Johnstone keeper's heroics last season as Callum Davidson's men sealed an unlikely double saw Clark's stature grow and a move to a bigger club could be in the offing.
Statistically, it isn't hard to see why. Clark is conceding 1.08 goals per game this season but with an xGA of 1.3, we can see that his team's plight would have been even worse without him.
Clark is preventing 0.22 goals per 90 minutes - which works out at a goal every four or five games - and like Siegrist, this is a continuation of a trend over the last few years. The 29-year-old consistently outperforms his xGA and could be a shrewd addition at Ibrox.
Sam Johnstone
The Manchester United goalkeeper has spent the season on loan in the English second tier at West Bromwich Albion where his performances have gained plenty of admirers.
Rangers are said to be interested in the Englishman but although the rate at which Johnstone concedes is relatively low - he shipped 0.84 goals per game this season in the league - we can see that he has been slightly underperforming in the Championship.
Johnstone has an xGA per 90 of 0.78, meaning that he concedes 0.06 goals per game that he really ought to be stopping, based on probability. Again, that might not sound like much but it can add up over the course of a season to have a telling effect on the team.
Martin Fraisl
The Schalke goalkeeper has played an important role as the German club sealed their return to the Bundesliga this season. Another who is out of contract this summer, Fraisl could represent a relatively cheap option for Van Bronckhorst.
However, the Dutchman would do well to note that Fraisl really should have been doing better this term. The 29-year-old conceded 1.15 goals per 90 this season with an xGA of 1.08, suggesting that he has been letting shots in that he really should be preventing.
It has cost Schalke 0.07 goals per game this year and leaves serious question marks hanging over his suitability for the No.1 shirt at Ibrox.
Vladan Kovacevic
The 24-year-old from Bosnia-Herzegovina is the latest name to be touted for a move to Ibrox and a quick look at his under-the-hood stats shows why Rangers have been credited with an interest in him.
Playing for Rakow Czestochowa in the Polish top flight, Kovacevic played an important role as the team secured a second-placed finish. He conceded 0.82 goals per game but it is only when we examine his xGA that his value becomes obvious.
Kovacevic has an xGA per 90 of 1.05 this season, meaning he has effectively been preventing 0.23 goals per game - or a goal every four matches, to put it another way. It's a trend throughout the shot-stopper's career and he consistently performs comfortably above the statistical average. He could be a very shrewd signing indeed.
