Former Celtic striker Jan Vennegoor of Hesselink admits he was surprised by Neil Lennon's decision to leave the club.
Lennon left the Scottish champions on Thursday after steering the Glasgow club to three league titles and two Scottish cups in four years, as well as qualifying for the last 16 of the UEFA Champions League in 2013.
And Vennegoor of Hesselink, who spent three years at Celtic between 2006 and 2009, told Sky Sports News he could see Lennon was management material when he played with him at Celtic Park.
"He took me under his wing in my first year at Celtic," he said. "Sometimes you can see with a player they have a manager in them and you could see that with Neil. Some players just have it.
"His leaving was a bit of a surprise. You could see the love for the club he had.
"He's leaving for a different challenge but I don't think that love has gone. It leaves a big spot here for a new manager and it's going to be a big task for someone who comes in."
Meanwhile, Vennegoor of Hesselink, who scored three goals in 17 games for Holland, believes Manchester United have chosen the right man in his compatriot Louis van Gaal.
"He is a top manager and has been successful all over Europe. If they can play in the way he wants them to, they will have great success. It will be a great adventure for him," he added.
"He knows what he wants, he says what he wants. He is a character and you need that at a big club like United and there will be some funny stories around him."
Vennegoor of Hesselink also backed former national team-mate Frank De Boer to be a success at Tottenham, should he make the move to north London from Ajax.
"I regard De Boer highly because he did a really great job when he came in as a young manager at Ajax," he added.
"They were champions four times in a row with good competition and he is also a character. He is an absolute winner.
"Any team that he coaches he could do a good job. Spurs are big club so we will see what happens."