After conceding 18 goals in just six Champions League group games and losing 4-0 to Hearts at the weekend, it’s no surprise to see Celtic close to bringing in a defender.

Last week RB Leipzig centre-back Marvin Compper was said to be a Celtic transfer target for January, with the Daily Mail saying he’s top of Brendan Rodgers’ January wish-list and today he's turned up in Glasgow ahead of a medical.

The 32-year-old is out of favour at RB Leipzig, having only started one Bundesliga game all season.

Who is Compper?

After spending most of his youth career with Stuttgart, he moved to Borussia Mönchengladbach in 2002.

Compper made 50 appearances for Gladbach’s reserve side, with his debut in 2003, scoring five times during his time with the club.

He made his senior debut in 2005, going onto make 33 appearances in total for the club, becoming a regular during the 2006/07 campaign.

The following season though, he only managed to play three times in the first-half of the campaign, which saw him look to leave the club, joining Hoffenheim in January 2008.

Compper spent five years with Die Kraichgauer, making 171 appearances for them, before wanting a change of airs and heading to Italy with Fiorentina.

He spent a season and a half with La Viola, making 26 appearances, and scoring one goal, in the quarter-finals of the Coppa Italia against Siena, the late winner in a 2-1 victory.

In August 2014, he returned to Germany with RB Leipzig, who were then in the German second division, looking to attract big-name players for their march up the league.

He was a regular for two seasons with Leipzig, helping them to promotion in his second year at the club.

That saw him move up with them to the German top flight, where he made 25 league appearances last season.

His game time has been much limited this season, playing just three times in total in all competitions, with two of them off the bench.

Compper is a one-cap German international, having played for Germany against England in November 2008, which made him the first Hoffenheim player to be capped by his country.

What are Compper’s main strengths?

There’s no doubt that Compper’s positioning is a real strength of his.

He has the ability that is so useful to good quality defenders of being able to read the game and knowing where to put himself so he can step in front of the striker and win the ball.

Above, you can see how after the ball comes in from a throw-in, Compper reads the bounce perfectly, nipping in in front of the Nürnberg attacker to take control of the ball.

Not only that, but he plays a lovely ball down the line to his team-mate, rather than just whacking it out into touch.

And that passing quality is something you notice when you watch the German play.

In the stills above, you can see how given a bit of space against Borussia Dortmund, he managed to pick out a beautiful long-range pass, right onto the chest of his forward, who could get free and in behind the defence.

Having someone like that, almost a quarterback, can be a real asset to any side.

And he can also be a threat in the opposition box too.

In the stills above, against Augsburg, Compper is never really picked up, and uses his intelligence to stay free of the opposition defenders, before getting into the danger zone in the last second and heading home.

What are Compper’s main weaknesses?

Occasionally Compper can be accused of overplaying, trying to take on his man one too many times, and that can lead to the opposition getting the ball in a dangerous area.

Of course, that’s not ideal for a defender, but many ball-playing centre-backs do make the odd error like that.

He is also occasionally guilty of switching off, which is also a worry in defence – think David Luiz in his first spell at Chelsea.

What’s more, he of course won’t be match fit having only started one game this season.

Key stats on Compper

Marvin Compper stats

How much is Compper worth?

Compper only has 18 months left on his contract, but RB Leipzig boss Ralph Hasenhüttl has implied he’ll have to put in a transfer request if he wants to leave, despite his limited game time.

He said: “I don’t want to get rid of any player in January.

“It’s a squad game and we need them all, especially as we have had a lot of injuries recently.

“Also, Marvin has never come to me and said he’s unhappy or put in a transfer request.

“So he will be here until the summer at least.”

The exact price Compper is arriving for is unknown, but it will unlikely be too cheap.

Why are Celtic signing Compper

There’s no doubt that Compper has quality that would add to Celtic’s leaky backline.

At 32, he’s not a long-term solution, but defenders can play well into their 30s and thrive, especially those whose game isn’t built on pace.

What’s more, with Rodgers’ side’s pace up front in Moussa Dembélé, Patrick Roberts and Scott Sinclair, his long balls out from the back could prove to be a real asset.

And after a 4-0 thrashing, which underlined weaknesses at the heart of their defence, bringing in a centre-back makes sense.

With midfielder Nir Bitton, full-backs Mikael Lustig and Kieran Tierney having to deputise there at times, it is a logical move to strengthen that position.