Adams died shortly after returning from the 2026 FIFA World Cup in North America, where he represented Bafana Bafana in three of their four matches as South Africa reached the knockout stages for the first time in their history.
The midfielder earned his return to the Bafana squad after an impressive second half of the previous season as Downs went on to be crowned African Champions, having missed out on the Africa Cup of Nations (AFCON) squad in Morocco.
Leon recalled the moment he learned of Adams' death while the Sundowns squad was preparing to travel to Austria.
"It was really tough, and it still is. We were due to travel to Austria that day, and everyone was in good spirits because the lads who'd been at the World Cup were joining up with the rest of the squad," Leon was quoted on the FIFA website.
"I arrived in a great mood, with my tunes on, but the news just left me shell-shocked. It makes your heart sink. He was someone I shared a lot of happy moments with, someone I laughed with, and someone I had such a close bond with."
Leon also revealed how coach Miguel Cardoso urged the squad to draw strength from the tragedy and honour Adams through their performances.
"The coach told us that we had to use it to become a tighter-knit group and that it was meant to prepare us for what lay ahead. To bring us closer together and do everything in his honour," the striker added.
"He was hugely important to the club and to us, and the first time I saw him play, I told the coach that he was a special player. It was incredibly sad."
Leon now turns his attention to Sundowns' FIFA Intercontinental Cup quarter-final against Asian champions Al Ahli SC at Loftus Versfeld on Saturday.
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