Mthethwa has been one of Stellenbosch FC's star players since joining from Black Leopards mid-way through the 2021/22 campaign and has featured in 18 of the club's 19 matches since making his debut.
The 27-year-old has become a trusted midfield enforcer under Stellies head coach Steve Barker who was quick to laud his performance after standing out during Sunday's MTN 8 quarter-final defeat against Kaizer Chiefs.
"I just don't know how a player like Sibongiseni Mthethwa cannot be close to the Bafana squad," Barker said during his post-match press conference.
"I have never seen a player with so much energy, power, strength and commitment. He seems to grow with energy the longer the game goes and it was again a top game from him.
Should Mthethwa catch the attention of national team coach Hugo Broos, he would become only the fourth Stellies player to represent Bafana Bafana after Athenkosi Mcaba, Antonio van Wyk and Jayden Adams.
This is the second instance in recent times that calls have been made for him to earn a call-up, with Barker having previously singled him out during the club's kit reveal at the start of the season as well.
"He is affectionately known as the OX, he plays like an Ox, and as the game gets longer and longer, the more energy he seems to get," he said on that occasion.
"He has been a great addition to our squad and we are expecting a massive season from him, and Bafana Bafana should be keeping their eyes and ears open because he is a top player."