Celtic tightened their grip on the Scottish Premiership title with a 4-0 win over second placed Aberdeen at Celtic Park on Sunday.
Goals from Jason Denayer, Leigh Griffiths, Gary Mackay-Steven and Stefan Johansen handed Celtic a comfortable win over the Dons, moving them six points clear of Derek McInnes' men in the table.
Celtic now have the chance to make that gap nine points with a win over St. Johnstone on Wednesday, with Ronny Deila's men pulling away in first place.
Many now expect Celtic to win the league for a fourth successive season, and that would mean qualification for the Champions League preliminary rounds this summer.
After failing to make it to the group stage last year, Deila will be keen to go one step better this time around, but one former Bhoys star expects big changes at the end of this season.
Walker spoke to Sky Sports News today, and believes that Virgil van Dijk will leave the club for a bigger move this summer, whilst the future of Manchester City loanees Denayer and John Guidetti are also up in the air - and he anticipates all three leaving this summer.
"I think the likelihood is that Virgil van Dijk will leave, I think he wants to go. Jason Denayer has said he wants to go back to Manchester City, and I think it's debatable whether Celtic will want to keep John Guidetti, who came on in the Europa League match and scored against Inter Milan. So you're going to see a number of changes, big changes," said Walker.
Losing both starting centre backs would be a huge blow for Deila and Celtic, but that's a very real possibility right now given admiring glances from Premier League clubs for van Dijk and how highly Manchester City rate Denayer.
Guidetti may still be at Celtic Park next season, but amid speculation that Marseille want to sign him when his contract expires this summer, there's no guarantee that he'll be back either - leaving Deila with plenty of holes to fill if they do leave.