Having joined the club's academy at the age of eight, Mason spent 17 years as a Tottenham player before signing for Hull in 2016. By the time of his departure he had played 70 first-team games for Spurs after getting a chance from Pochettino during the 2014/15 campaign.
"Sure he was a very successful player, and sure he will be a very successful person in football, and everything that he is going to do. It is very sad news but it opens up a massive future (for him)," the Spurs boss is quoted as saying by Sky Sports.
"He is 26 but he is an amazing person and has an amazing football brain," he added.
"Of course the door is open to help him; myself, the coaching staff and the club, because we love him and all his family. In the last few days he was at the training ground. He was talking a lot with us, the coaching staff and [academy boss] John McDermott.
"Don't worry Ryan because you are going to be a successful person in football outside of the pitch, no doubt about that."
Mason was 23 before getting his break at Spurs and had been on loan at five different clubs in England and France in the seasons before Pochettino's arrival.
The Argentine remembers bonding with Mason during a half hour conversation in the airport ahead of Spurs' pre-season tour of the United States in 2014 and was convinced he had a 'good player' at his disposal after watching the midfielder in action for the first time.
"In the first game we played against Seattle, he understood everything," Pochettino recalled.
"After only a few tactical training sessions he was quick and he understood everything - the movement and the timing and the concept - that maybe for another player it takes a whole season, and I said 'we have in front of us a very good player'."