The Ivorian started his professional career in Rotterdam where he spent three years with Feyenoord, scoring 42 goals in 82 appearances.
Kalou’s impressive displays led to a six million euros move to Chelsea in 2006 before he moved on to Lille and then Hertha in 2014.
The 31-year-old is understood to be on the verge on signing a new deal with the German outfit,but has admitted he hopes to head back to Feyenoord in the future.
Kalou said: “I feel fit and think I have a lot of good football in front of me for years. My dream is to end my career at Feyenoord. The club is in my heart, because everything began for me there.
“Because of Feyenoord I’m the player and person I am now.”
Southampton have announced plans for a two-week tour of China as part of their pre-season preparations for the 2018-19 season.