Rangers have agreed a fee with Slaven Belupo in the region of £2m for Croatian defender Nikola Katic, according to Sky sources.
This is subject to a medical, which Sky Sports News understands is imminent.
The 21-year-old has won one cap for the Croatian national side, making his debut as a substitute in the 2-1 friendly win over Mexico in Los Angeles in May last year.
If the deal is completed, Katic could be joined by Connor Goldson at Rangers, as Sky sources understand the club have agreed a fee with Brighton in the region of £3m for the defender.
Rangers have already signed Ovie Ejaria on a season-long loan move from Liverpool and completed permanent deals for Jamie Murphy, Scott Arfield and Allan McGregor.