The 27-year-old, who has fallen out of favour at White Hart Lane, has been closely monitored by the Black Cats this summer.
It is unclear whether the Croatian will join the North East club on a permanent deal or a loan agreement. However, Kranjcar’s agent Adrian Aljai is confident a deal is imminent.
"We are about to close a deal with Sunderland," the Daily Express quotes Aljai as saying.
"I believe that is the best solution for Niko."
The midfielder, who started just two games for Spurs last season, moved to White Hart Lane from Portsmouth in 2009.