The SPL leaders have been linked with Samuel Slovak who played for Spanish second division side Tenerife.
The 25-year-old midfielder would be available for a £700,000 fee and it is hoped that he might persuade Moravcik, who has hit four goals in his last four games, against retiring at the end of the season.
It is believed that former Celtic boss Jozef Venglos - the man who brought Moravcik to Parkhead two years ago and is now currently acting as their talent scout in Europe - has recommended Slovak to Martin O'Neill.
Venglos has been in Glasgow for the last week meeting Celtic officials and got together with his favoured son Moravcik at the weekend after Lubo scored in the 6-1 rout of Hearts.
Slovak is keen to quit Tenerife after falling foul of Spanish League rules that only allow six non-EU players per club, following the recent acquisition by the island team of two Argentineans and a Brazilian, which has taken them over their quota.
The right-sided midfielder is due to qualify for Spanish citizenship in the next month, which would circumvent any work permit problems Celtic might have.
Venglos appealed at the weekend for Moravcik, now 36, to think again about quitting and play for another season.
Meanwhile, Chris Sutton is rated as doubtful for the Old Firm clash on Sunday after injuring his toe against Hearts.
Celtic physio Brian Scott said: "The toe is not broken and it is a matter of how quickly it heals but he must be considered doubtful."
