The summer transfer window has just one month left in it. And so far, Celtic have only been able to make two additions, albeit very promising ones.

Camilo Duran has arrived from Qarabag and has looked like the real deal in pre-season. At the same time, Kasper Hogh has become the record signing in Celtic history.

Could Martin O'Neill be bringing back two up front, like his original stint as Celtic manager, having seen the Hoops struggle to find the back of the net last season? Time shall tell.

It is worth pointing out though that there are other areas of the pitch where Celtic need to strengthen as well.

One of them is their midfield with it looking likely that both Arne Engels and Reo Hatate will leave at some point in this summer transfer window, with the former in particular receiving a lot of attention.

According to Football Insider, Celtic must offer around £4.3 million (€5 million) in order to sign Mika Baur after seeing multiple bids rejected by SC Paderborn. 

SC Paderborn want at least £4.3 million to part ways with Baur. The German club have already turned down a bid worth £4 million from Celtic.

The gap between the two is not much though. So, one would hope that Celtic meet SC Paderborn's valuation with their next offer and get a deal over the line.

There is no point in allowing this to drag on for much longer. The Premiership season has already kicked off.

The later a player arrives, the more time it will take for them to adjust to their new surroundings. And Engels has already agreed personal terms with West Ham United. So, he is clearly eyeing the exit door.

Baur is coming off an excellent campaign. He was named SC Paderborn's Player of the Season as they secured promotion to the Bundesliga.

So, it is not hard to see why Celtic might be keen on signing the German midfielder, and also why SC Paderborn might not be eager to part ways with him unless their transfer valuation is met.

READ MORE: 'Reached a verbal agreement' - Celtic Transfer Advances

One thing working in Celtic's favour is the fact that the player wants the move. In fact, reliable sources have confirmed that personal terms have already been agreed.

Now, it is about agreeing on a transfer fee. And one would hope that does not prove to be a stumbling block.