The 21-year old has been drafted in as a replacement for the departed Virgil van Djik.
The loss of commanding centre-back Virgil van Dijk is a huge blow but McKinlay – who appeared 90 times for the Bhoys between 1994 and 1999 – feels Simunovic is a more than adequate replacement.
“Virgil wanted to go elsewhere and that’s what happened, but with Jozo Simunovic coming in there is plenty at the club,” said McKinlay.
"Here is a guy who has already played over 100 times for Dinamo Zagreb, has captained Croatia’s under-21s and already has great pedigree.”
The Croatian international arrived in a £5.5 million deal, according to the Herald, and has big boots to fill at the heart of Celtic’s defence.
McKinlay is convinced he is up to the task however, after taking in some videos of the young talent.
"I have seen a lot of footage of him, he’s a fantastic footballer. So it will be seamless with him coming in and Van Dijk going.
"Certainly, from what I have seen, he can come in and do a fantastic job for Celtic. He is Rolls Royce material and he can certainly make a big impact in the Scottish game," said McKinlay.
Hoops fans will be hoping McKinlay is proved right, but there remain doubts over the depth of quality in defence for Celtic.
Dedryck Boyata has proven himself to be a competent SPL defender but has looked vulnerable against stronger opposition in Europe.
Beyond the newly-arrived Simunovic, Charlie Mulgrew and Efe Ambrose make up the reserves, while Tyler Blackett’s impact remains to be seen.
The Manchester United loanee will provide cover at left-back however, a position where Celtic lack quality beyond Emilio Izaguirre.
This summer’s transfer window has been mixed for Celtic, and their latest arrivals will need to hit the ground running if the Bhoys are to maintain a challenge on all fronts.