Leicester City have signed full-back Danny Simpson from Queens Park Rangers for an undisclosed fee.
Gus Poyet revealed his desire to keep his Sunderland squad intact, but remains coy on potential signings.
The 33-year-old still has a year left to run on his contract with Wolfsburg, but he does not expect to extend that deal or move to another side in the Bundesliga next summer.
"This is probably my last year in the Bundesliga," he told Sports Bild magazine.
"If my body allows it and I am still fit, then maybe I will play on for a year in the USA or in Dubai after my Bundesliga career."
Olic won the Bundesliga with Bayern Munich in 2010, but was twice on the losing side in a Champions League final for the Reds.
Before moving to Germany, initially joining Hamburg in 2007, he lifted the UEFA Cup with CSKA Moscow while he has appeared 84 times for Croatia, scoring 16 goals, one of which came during the 2002 World Cup.