In the past two years Sundowns have lost as many skippers.
Alje Schut retired at the end of 2014/15 after lifting the Nedbank Cup to return home to the Netherlands.
Fellow defender Ramahlwe Mphahlele later traded Downs for Kaizer Chiefs after leading the Brazilians to league honours last term.
Mosimane, however, doubts Kekana will be tempted away from Chloorkop save for a move overseas.
"I'm not worried about Hlompho, maybe. Hlompho, if he has to move he has to go overseas hey. Where's he going? Does he want to play [CAF] Champions League or not? Does he wants to play Champions League?
"You can choose to go to a team that doesn't play Champions League, it's up to you. Champions League is big hey and we take you to the [Club] World Cup and give you a position in Bafana Bafana, so you choose what you want.
"Don't forget we look after our players and I think you know what happens to prize money when we win any cup. So you really want [to leave] that? You know how many trophies we won last year? And the president [Patrice Motsepe] gave us all the money, all.
"I think he should think about it, how much is that if he wants to cross the floor because of the salary, because someone is paying you R10 000 more at this level.
"To Kekana, it's not about that and it is very difficult to outbid Sundowns, not because of the money, because of all the prestige."