The Hornets want to boost their firepower and have turned to Rajovic, who has been turning heads in Swedish football, as a possible solution.
Kalmar’s coach has remained coy on the possibility of Rajovic joining Watford, but the Championship side are in talks with the Swedish team.
Watford want to sign Rajovic before the transfer window closes, according to Swedish daily Expressen, and a bid has gone in.
The Hornets are claimed to have offered just over £1.1m for Rajovic.
The hitman, who has seven goals in 20 Allsvenskan games this season to his name, would put pen to paper to a long term deal at Vicarage Road if the deal happens.
Losing Rajovic would be a blow for Kalmar, especially in the middle of the Swedish season.
Kalmar left Rajovic out of their side for Wednesday’s Swedish Cup clash, something which raised further transfer speculation.