The ex-Manchester United midfielder, who spent a stint with the Hoops in the latter stages of his playing career, has emerged as a favourite to replace Neil Lennon as the club's next permanent manager.
Keane himself is remaining tight-lipped over a potential return to Glasgow, but recent reports claim that former United teammate Nicky Butt is already being lined up as his number two.
Butt left a long-term role with Man United’s academy system last week.
Speaking on Sky Sports’ Football Show, Donnelly suggested that the prospect of the duo taking over at Celtic is one he can get behind.
He said: “Roy Keane excites me.
"People have their doubts about Roy Keane, but I think he’s a winner, and I think coming into Celtic to go head-to-head with Stevie Gerrard would be something that would excite everybody.
"That’s an interesting one.
"Nicky Butt coming in alongside him – I’d be happy with that”.
Keane spent the second half of the 2005/06 season with Celtic after completing a free transfer from Man United in the January transfer window.
The 49-year-old made 10 appearances for the Bhoys, and helped them to lift a Scottish league title.
Aside from his punditry work, the fiery Irishman’s last job in football came as assistant manager alongside Martin O’Neill at Nottingham Forest in 2019.
Keane’s last role as a first team manager in his own right came at Ipswich Town, with his tenure at Portman Road ending in 2011.