When Simon Mignolet arrived at Liverpool in the summer of 2013 for a fee of £9 million signing on a five-year contract, then manager Brendan Rodgers hailed him as "one of the top goalkeepers in the Premier League." 

Since his debut against Stoke City, when he became the hero for saving an 89th-minute penalty, Mignolet has proved that he can perform at a high level in the Premier League, but his recent his ability to consistently perform at such a level is doubted by many fans.

Jürgen Klopp's arrival at Liverpool has given the fans confidence that he can help Liverpool rise to the same echelons that he took his former club, Borussia Dortmund, to.

But despite a strong start, Liverpool have had some shaky performances recently, including away losses to Newcastle United and Watford and a home draw to West Brom.

As such, many fans have been clamouring for the club to make signings in the January transfer window. With goalkeepers a major issue at the club, many fans feel that a new one is a top priority when the January transfer window arrives. Though Klopp has recently defended the Belgian by saying "I've had a lot of goalkeepers over the last few years and Simon Mignolet is one of the smartest I have had" - should he be in the market for a new shot-stopper? 

Who would Klopp target as his replacement?

One popular choice is Bayer Leverkusen's Bernd Leno. The German is only 23 years old and has played a key part in Leverkusen's first-team in recent years. The problem, however, is he would command a hefty price tag and it would take a lot of persuasion to get him to leave Leverkusen for Liverpool.

Another option is Stoke City's Jack Butland, who like Leno, is a young 'keeper who has had lots of first team experience. He could potentially be signed for a smaller fee, however, the 22-year-old has never played a European fixture, which could be a major long term problem for Liverpool, who are aiming for Champions League qualification.

The final name that has been commonly talked about is FC Barcelona's Marc Andre Ter-Stegen. The young German k'eeper had an incredible 2015. After signing with the Catalan giants from Borussia Mönchengladbach, Ter-Stegen went on to win La Liga, the Copa Del Rey and the Champions League.

Despite all the glory, he has struggled to get games, having to regularly compete with fellow goalkeeper Claudio Bravo. This could mean that the youngster could be open to a move to Merseyside. A major downside to this is that it would take a lot of money to get Barcelona to let him go, and for Ter-Stegen himself to leave sunny Spain.

Of course, Liverpool do have the option of playing backup keeper Ádám Bogdán. However, after his disastrous showing in a lacklustre 3-0 defeat to Watford, it seems unlikely that Klopp sees Liverpool's long-term goalkeeping future lying in the hands of the Hungarian.

It looks promising when looking at Jürgen Klopp's transfer history, with the German signing players such as Mats Hummels, Robert Lewandowski and Marco Reus for a combined fee of just over €30m.

This looks even more impressive when compared to Brendan Rodgers' signings of Christian Benteke for £32m, Dejan Lovren for £20m and Mario Balotelli for £16m - but does that mean Klopp should be looking for his next shrewd purchase in between the sticks?

Comparing Mignolet to other goalkeepers

The biggest clubs in England all strive for UEFA Champions League qualification, despite English clubs rarely getting far into the tournament.

Liverpool are no different and fans seem to expect finishing in the top-four every year. However, the goalkeepers at other top four clubs seem to be on a slightly higher level than Mignolet. 

Arsenal's Petr Čech is one of the main names that stands out, as he is one of the most experienced goalkeepers in the league. He boasts multiple league titles, FA Cup wins, a Champions League and more. He's made nearly 500 appearances for club and country since 1999 and kept a record 220 clean sheets for his former club Chelsea in all competitions. He can barely be compared to Mignolet, who currently holds the record for "goalkeeper who has made the most errors leading to goals" since he joined Liverpool in the 2013/14 season.

Although Mignolet can't be blamed for all of the 112 shots that ended up in the back of his net, he has conceded 23 more goals than Manchester United's David de Gea and 36 more than Manchester City's Joe Hart. The Belgian has also only saved 67.6% of shots fired at him.

However, Mignolet has had a good record so far with clean sheets. Only Joe Hart has kept more since the 2013/14 season, and the Belgian is currently on the same amount as David De Gea.

The Liverpool keeper is also very prone to punching the ball from crosses, opting to do so 80 times in the past three seasons, more than any other keeper in the league and has opted to punch out the ball more times than he has caught it, and is the only keeper in the league to accomplish that.

The majority of these stats don't sway in Mignolet's favour. But I think it is unfair to use him as a scapegoat. The club's defence on a whole is also far below the standard of other top four clubs and is a major reason as to why Liverpool so frequently fail to achieve Champions League qualification.

But despite the fact he can be an excellent goalkeeper from time to time, he is very inconsistent and is a major reason as to why Liverpool aren't winning as many games, and as much silverware, as they could and should be. 

My opinion 

In my opinion, Mignolet should not be given a four-year contract by Liverpool as his mistakes have led to multiple goals and those goals have led to the club losing matches. His stats prove that he isn't a good enough keeper compared to goalkeepers at other top-four clubs and that the Reds must upgrade upon Mignolet to consistently achieve Champions League football.

However, I do feel that the club shouldn't sell him as he would be a valuable backup to a new first-team goalkeeper, if the new No.1 was to be injured, suspended or go through a poor run of form. He has also proved on several occasions that he can be an excellent goalkeeper, but he simply isn't consistent enough to maintain his spot as Liverpool's number one goalkeeper for the foreseeable future.