SunSport understands the former Republic of Ireland winger who won two Premier League titles with Chelsea has held talks with the Scottish Premiership champs after Shaun Maloney left to become Belgium No3.
But Duff, 39, faces stiff competition as Celtic were inundated with applicants to succeed former Scotland midfielder Maloney.
Former Blackburn, Newcastle and Fulham star Duff, who won 100 caps, is currently Shamrock Rovers Under-15s boss in his homeland.
And he knows Celtic chief Brendan Rodgers well from his time at Stamford Bridge.
Rodgers, 45, was Chelsea youth coach from 2004-2008 before managing Watford, Reading, Swansea and Liverpool.
He then took over Celtic in 2016.
The Hoops have been searching for a new Under-20s chief since Maloney, 35, left in September to work under ex-Everton manager Roberto Martinez.
Dublin-born Duff has yet to have a senior role in coaching.
But he already has a good reputation at Shamrock after finishing his playing career there in 2015.
Duff is best known for his three years at Cheleea.
Apart from lifting the Prem crown in 2005 and 2006, he also won the League Cup.
Then he helped his next club, Newcastle, win the Intertoto Cup.
After exiting Fulham in 2014, Duff spent a year Dwon Under with A-Leaguers Melbourne before switching to Shamrock.
Source: Read Full Article