The 29-year-old will spend the rest of the season playing for coach Gavin Hunt in the Cape Winelands, and will hope to score the goals that could put him back in the frame for a 2026 World Cup place.
Mabasa had fallen far down the pecking order at Pirates, starting just two games all campaign to go with three substitute appearances.
He had not played for The Buccaneers since a Carling Knockout win over Siwelele in early October. He did manage a goal against TS Galaxy in the league in late September, and also scored against Stellenbosch in the
Mabasa is in his second spell at Pirates and has 49 goals in all competitions, three shy of the club’s record scorer in the Premier Soccer League era Benedict Vilakazi.
Stellenbosch have been linked with several players in recent weeks as they begin a rebuild under Hunt, looking to move away from the Betway Premiership relegation zone.
Their first game after the break for the Africa Cup of Nations is on Tuesday away at Sekhukhune United.
Stellenbosch are also competing in the CAF Confederation Cup group stages.