Celtic have been left to rue their decision to allow goalkeeper David Marshall to depart Parkhead just over 15 years ago, with the former Scotland international having since gone on to enjoy an impressive career for both club and country.

The 6 foot 3 colossus had previously been part of the Old Firm side's youth set-up, eventually registering 44 appearances in all competitions for the club after making his debut off the bench in a Scottish Cup tie against St Johnstone back in 2003.

The then-youngster notably stole the headlines for his display against La Liga giants Barcelona in a UEFA Cup clash at the Camp Nou in March 2004, making a string of fine saves as the Hoops progressed to the next round.

The Glasgow-born gem again impressed when the two sides met the following season, this time in the Champions League, saving a penalty from Brazilian icon Ronaldinho in the 3-1 loss at Celtic Park.

Despite that sparkling start to life in the first team, the boyhood fan struggled to nail down a regular starting berth and was eventually sent on loan to Norwich City in January 2007, before subsequently joining the Canaries on a permanent deal later that year.

The goalkeeping titan had seemingly been in search of regular game time after falling out of favour under Gordon Strachan, with the Carrow Road outfit striking a deal for something of a bargain fee in the region of £360k, as per Transfermarkt.

That decision to let him depart has backfired spectacularly, with Marshall proving himself a reliable presence at a number of clubs across the footballing pyramid in England, having now racked up 588 senior club appearances to date.

His finest hour arguably came at international level, however, with the 46-cap gem emerging as a national "hero" - in the words of Pete Wishart - after helping Steve Clarke's side secure a place at Euro 2020 following his penalty shootout heroics against Serbia.

Such form had seen pundit Davie Provan tip Celtic to make a move to bring the 'keeper back to the club last summer as a strong understudy to Joe Hart, albeit with Ange Postecoglou and co seemingly passing up the chance of a reunion.

A year earlier the player himself had issued something of a come-and-get-me plea amid his impending departure from Wigan Athletic, although the Scottish Premiership side - then managed by Neil Lennon - ultimately turned to £4.5m man Vasilis Barkas instead.

The 37-year-old has since made a return to Scotland for the first time since his initial exit from Celtic Park, joining Hibernian earlier this summer, with the Old Firm outfit hoping the veteran gem doesn't steal the show when the two sides meet this season.

They are already ruing his departure as it is.