Tottenham Hotspur defender Kyle Walker was keen to wish his former teammate well.
Philippe Senderos is reportedly a target for Rangers.
The defender is one of eight new signings at Newcastle United this summer.
The defender has been impressed with the Spurs boss over the last couple of years.
Celtic won 2-1 against Astana in Champions League qualification yesterday.
Summer signing Moussa Dembele’s first goal for Celtic was crucial, earning victory against Astana and a place in the Champions League play-off round.
Can has two years remaining on his current Liverpool deal.
Celtic progressed to the next round of the Champions League on Wednesday evening.
The Nigerian international was in sensational goalscoring form against Barcelona in Stockholm.
The Benin striker has been earmarked as a potential recruit by the Cottagers.
The former Burnley, Bolton Wanderers and Wigan Athletic boss parted ways with the Houston Dynamo by mutual consent this week after a disappointing 18-month stint in the USA.
The Tottenham chairman was in a meeting with the Tottenham Hotspur Supporters' Trust this week.
The Scottish midfielder has been in great form for Sheffield Wednesday this season.