The defender joined Celtic on a free transfer this summer.
The BBC Sport pundit is unconvinced by the Brazilian, who completed a shock return to Stamford Bridge on Deadline Day.
Should Everton make a move for high profile free agent Sulley Muntari?
Nottingham Forest owner suggests he may not sell up entirely.
Max Verstappen, who appears to have derived his driving technique from watching Ben-Hur, has certainly divided opinion in Formula One. The 18-year-old is either Mad Max or the most exciting new talent the sport has seen since Ayrton Senna burst on the scene in the mid-1980s.
Max Verstappen has compared himself to Zlatan Ibrahimovic after brushing away criticism of his aggressive overtaking and defensive methods in recent races.
Tony Blair has claimed Britain could remain in the European Union, despite the referendum result in favour of Brexit, if public opinion shifts in the next few years.