GARY MACKAY-STEVEN reckons Celtic could look back on John Souttar joining Rangers and feel like it was a transfer "that got away".

The 25-year-old Jambos defender, who has battled back from three serious Achilles injuries among other setbacks, has signed a pre-contract deal to join the Ibrox club in the summer. 

Hearts teammate Mackay-Steven was quizzed on why his old team Celtic never made a serious move for Souttar on Open Goal.

He said: "I'm not sure, it's surprising.

"He proved [against St Johnstone], he just strolled the game and it was one of his better performances under all that scrutiny.

"I know Celtic have the boy Welsh, who has done really well. They've signed Starfelt and a few centre-halves.

"They've obviously spent money on bringing all the Japanese boys from the league that the manager used to be in.

"Maybe that was their main focus and he just wasn't their top choice.

"Maybe it's just the one that got away, I don't know but he's a top, top player."

The long-serving defender angered some of the Tynecastle club’s fanbase when it was confirmed last Friday that he had agreed a pre-contract with cinch Premiership rivals Rangers.

The Scotland centre-back was booed throughout the 2-0 win over St Johnstone by several home supporters, although others tried to drown out the noise by applauding whenever he touched the ball.

Souttar looked unfazed by the situation as he delivered an assured display.

Mackay-Steven added: "John has every attribute. I think everyone knows he's a good player but [against St Johnstone] he almost thrived on it."