Celtic won against Heart of Midlothian at Celtic Park at the weekend to end the Scottish Premiership campaign unbeaten.
Celtic striker Leigh Griffiths is one of the best players in the Scottish Premiership.
Celtic left-back Kieran Tierney is one of the best defenders in the Scottish Premiership.
Glasgow Rangers recently terminated the contract of Joey Barton.
Ibrox side Rangers won against Old Firm rivals Celtic in the semi-finals of the Scottish Cup on Sunday.
Norwich City and Queens Park Rangers-linked James Forrest recently turned down a new contract offer from Celtic.