Inter are looking to strengthen their attacking midfield options after selling Philippe Coutinho to Liverpool, and Kuzmanovic, 25, is poised to join along with young Croatian starlet Mateo Kovacic.
Inter confirmed via their website that Kuzmanovic took part in a training session, but are yet to confirm any deal has been completed.
According to reports in Germany, the Serbia international will officially become an Inter signing later today, signing a four-and-a-half year deal.
Kuzmanovic, who scored 17 goals in 96 Bundesliga appearances, is available at a knock-down price with his Stuttgart contract expiring in the summer.
Kovacic was also due in Milan today to have a medical, according to his current club Dinamo Zagreb.
The 18-year-old playmaker, who has already drawn comparisons to Luka Modric, will command a fee of around 11million euros, according to several reports.
"It all happened so fast and I'm still in shock, I do not even know what to say," Kovacic told Dinamo's website of the deal.
"Dinamo is my club and my home, so I find it hard to leave, but an offer from a club like Inter Milan, one of the biggest in the world, cannot be refused.
"Of course, it's not over and I'm waiting for my medical examination, but I believe this is just a formality."
Kovacic joined Dinamo as a youngster in 2007 from Linz. He was born in the Austrian city, but is eligible for Croatia through his parents.