Celtic have made an official offer for Atalanta BC right-back Timothy Castagne, according to a report.
The 23-year-old is said to have been targeted as a potential replacement for Mikael Lustig, who is wanted by AIK Stockholm.
Castagne is contracted to Atalanta for another 18 months and the Serie A outfit do not want to cash in, but the Daily Mail suggests that Celtic have still pushed ahead with a £6m bid.
Speaking earlier this week, the three-cap Belgium international admitted that he will consider a January switch as he has managed just six league starts for his club this term.
Brendan Rodgers is also believed to be keen to sign highly-talented youngster Timothy Weah on loan from Paris Saint-Germain.
