Kovacs has made 55 appearances for Chesterfield after signing from MTK Budapest in August 2005. He spent a month on loan at York City in early 2007, but became a first team regular last season. He scored twice for Chesterfield, including one against City at Sincil Bank in their 4-2 win back in November.
Imps assistant manager Iffy Onuora told BBC Radio Lincolnshire: "We're a little short of bodies at the back after releasing Adie Moses.
"Kovacs is one of a number of players we're interested in, but it hasn't really gone any further than that yet."
The Imps would have to pay compensation for the 22-year-old, who has been offered a new deal by the Spireites.
If City were to capture Kovacs it would seem to signal a certain level of ambition that the club could attract other teams players.