The Spanish club have shipped the Dutch striker out on loan to the Eredivisie side, while securing the services of Senegalese striker Babacar on a temporary basis.
The 23-year-old attacker joined Real Sociedad from Ajax in the summer of 2010 but struggled to impress at the Liga outfit, making just two starting appearances since his arrival.
Sarpong, and Under-21 Dutch international, is hoping to gain more experience before returning to Anoeta for the final year of his contract with the Spanish side.
He could make his debut for NAC Breda, who sit 12th in the Eredivisie standings, on Saturday, when the club travel to Vitesse.
Meanwhile, Racing Santander have signed Fiorentina striker Khouma Babacar on loan as the 18-year-old Senegalese looks to grow under Juanjo Gonzalez.