The former Celtic striker was not impressed with the performance of Simunovic against Rangers at Ibrox in the Old Firm derby last weekend.
The 23-year-old central defender had a poor game and was also sent off, although Brendan Rodgers’s side managed to win the Scottish Premiership match 3-2.
Sutton wrote in The Daily Record: “A year ago Jozo Simunovic was smashing into Kenny Miller and hailed a hero but he’s gone backwards at a rapid rate.”
Simunovic is a very good defender and is one of the best in the Scottish Premiership, but the performances of the 23-year-old on many occasions have been disappointing.
It is clear that the central defender needs to improve, and perhaps he will in the final weeks of the season.
Celtic signed the defender from Dinamo Zagreb in the summer of 2015 for a transfer fee reported by The Daily Mail to be worth £3 million.