This was confirmed by Highlands coach Owen da Gama after his side edged Golden Arrows 2-1 at Makhulong Stadium on Sunday.
Senegal-born Sarr linked up with the Lions of the North on Thursday and Da Gama said he has already made his recommendation to the club's management.
“Issa Sarr is training with us currently. We don’t want this to be heard from the street,” Da Gama told reporters.
“We want it to be heard from us. We are trying to bring a little bit of experience to help us. As you know we brought the bulk of NFD players [up to the PSL] and we had to give them a chance.
“He started on Thursday and we are allowing him to settle in, and there are also negotiations going on.
“The nice thing about him is that he's got his papers (permanent South African residence) now. He is a South African and that makes it a little bit easier. We can recommend but the final decision is with the management.”
Da Gama also gave an update on ex-Pirates striker Tendai Ndoro, who is likewise training with Highlands while negotiating the terms of a potential deal.
“Tendai has been training with the team. You know he is a big player, there is no doubt about it. But big players come with a big prize. It is now between the management and his agent. We will see what happens, but I like him.
“Every player has a price. We will wait for the situation [to unfold] but I’m pretty sure that a decision will be made either way.
“He is a player that can score goals and with his experience he will certainly help us.”
Meanwhile, Da Gama said he decided against signing former Kaizer Chiefs winger Abia Nale.
“Abia Nale was training with us but unfortunately in the position that he is playing we got a lot of players. He is still a good player and I’m sure he will play in the NFD or PSL.”