This is according to Sundowns head coach Pitso Mosimane, who identified Mahlambi as a possible replacement for Percy Tau at the club.
Mahlambi, 20, joined the Brazilians from Egyptian Premier League champions Al Ahly on PSL transfer deadline day last week.
“We have invested in him for five years and we are in for the long haul," Mosimane told the media.
Mosimane added that he signed Mahlambi to score goals for them the same way Percy Tau did before he left for Brighton & Hove Albion last month.
"We need him to score goals for us because Tau was scoring goals for us, and we want that from Mahlambi because he will be key for us this season,” he continued.
The South Africa international, who won the 2017/18 PSL Player of the Season award, shared the league's Golden Boot with Polokwane City striker Rodney Ramagalela after netting 11 league goals for Sundowns.
The Brazilians also signed forward Jose Ali Meza, midfield maestro Andile Jali, left-back Lyle Lakay, left-winger Tony Silva, goalkeeper Reyaad Pieterse, attacking midfielder Lebohang Maboe, defender Mosa Lebusa as well as attacker Mahlambi during the recent transfer window.
Mosimane said that it could take two seasons for the 2016 Caf Champions League winners to return to their best.
“I have to give my team a chance to play together and get our new combinations right," the former South Africa head coach said.
"The team might come back in two years because it takes time to get it right, and we must be patient," he concluded.