The German defender left the Hoops this month following an ill-fated 18-month Parkhead spell.
Celtic have failed to acknowledged Marvin Compper's departure.
Christopher Jullien, Boli Mbombo and Luca Connell have signed for Scottish Premiership champions Celtic with Youssouf Mulumbu and Marvin Compper gone.
Celtic have let Marvin Compper leave the club for Duisburg.
Marvin Compper appears to have left Celtic with cult-hero status after making just one appearance in 19 months.
The curious case of Celtic centre-back Marvin Compper.
In a world of 25-man squads but still only 11 starting berths out on the pitch, it’s inevitable that some players are going to struggle for game time. Balancing a squad and keeping everyone happy is actually one of the most difficult aspects of modern football management, and we see footballers seeking out pastures new when they aren’t getting enough minutes out on the pitch every transfer window.
Marvin Compper was given a winner's medal for Celtic today.
Celtic boss Neil Lennon is short on central defense options.
The mysterious Celtic defender popped up with a goal for the reserves today.
The Whites of Marcelo Bielsa will host Sabri Lamouchi's Reds at Elland Road in the Championship on 10 August.
Tottenham Hotspur have been tracking the Real Betis man all summer long. .
Tottenham Hotspur won't be signing Paulo Dybala unless two big players leave first.
Premier League rivals Everton and Wolverhampton Wanderers have both been linked with Mainz's Bundesliga powerhouse Jean-Philippe Gbamin.
Bojan could be set to leave Leeds United's Championship rivals.
Tottenham Hotspur striker Harry Kane has hit one goal over pre-season so far.
Tottenham Hotspur and Everton reportedly want to sign the Ajax winger.
Newcastle United boss Steve Bruce was initially expected bring in a central midfielder at St. James' Park this summer.
Tottenham Hotspur were beaten 2-1 by Manchester United yesterday, with Mauricio Pochettino's side falling to their first defeat of pre-season.
Aston Villa paid a club-record £26m to sign Tyrone Mings from Premier League rivals Bournemouth.