The young Croatian believes he will fill the sizeable void left by Virgil van Dijk.
The talented youngster arrived late in the window and made the Dutchman’s move south of the border a little more palatable for the Parkhead faithful.
“I’ve come here and I believe in myself and I believe that I can play for this team. The manager has not said I’ll go straight in but we’ll see what he decides. For me it’s about training so we will see,” said the Croatian, in an interview with Celtic TV.
“I played against Virgil last year in the group phase of the Europa League and I know he left to go to England, but now I’m No.5."
The 21-year old arrives from Dinamo Zagreb with great pedigree, having captained Croatia at Under 17, 19 and 21 levels, and gave some insight into his game for those a little less familiar.
“I have a good jump, I’m fast and I’m strong. The coach knows why he signed me and I can help this team and that’s what’s important.”
A starting berth will undoubtedly be his soon, with Ronny Deila appearing unconvinced by Charlie Mulgrew thus far, and with big fixtures coming thick and fast, the youngster may find himself being thrown in at the deep end.
Dedryck Boyata had started to form a solid partnership with the now Southampton-owned van Dijk, and will need to become familiar with his new colleague sooner rather than later.
The Hoops' Europa League opener against Ajax is seven days away, meaning Simunovic has just this weekend's Scottish Premiership clash with Aberdeen as a warm-up before Celtic launch their assault on Europe.