What can we tell you about the teenager from Hajduk Split?
A deal in the region of €2-3 million is being mooted for the player - and he will then be likely to go back to Hajduk on loan.
So what can we tell you about him?
Here are five facts on the talented midfielder...
1) Despite being a Croatian international at under-16, under-17 and under-19 level - Pasalic was actually born in the German city of Mainz.
He could however be set for a shock call-up to the Croatian national team for the 2014 World Cup in Brazil.
2) His long-awaited debut for the club was expected to be made at the beginning of the 2012-13 season.
Unfortunately it was delayed after he picked up a serious case of Staphylococcus which kept him out for the majority of the campaign.
He eventually made his league debut for the club on April 14th 2013.
3) He has since gone on to be a very impressive member of the team. In his 16 league games for the club this season he has managed to score six goals - which quickly alerted big teams to his potential services.
4) As well as Chelsea he has also been a transfer target for the likes of Tottenham Hotspur, Liverpool, Eintracht Frankfurt and in particular Lazio.
Lazio apparently agreed a deal with the player last week - but did not meet the clubs valuation so he re-entered the market - and was snapped up by Chelsea.
5) At 6ft 1ins he is not your atypical ‘next Modric’ type.
In fact he has more resemblance in playing style to a former Chelsea player - German legend Michael Ballack.
Here he is scoring an inventive goal against fierce rivals Dinamo Zagreb…
image: © Jason Bagley