In Season 90, he was one of the notable snubs from the NCAA All-Star Game, despite averaging 11.8 points, 5.5 rebounds, 3.6 assists, and 1.9 steals.[4] Still, he was chosen to participate in the Slam Dunk Contest.[5] He scored 19 points in a win over the Perpetual Altas to end the first round of eliminations.[6] Unfortunately, the Blazers didn't make the Final Four due to a loss to the Letran Knights.[7]
In Season 91, Grey became the leader for the Blazers after Mark Romero and Paolo Taha turned pro.[8] In a win against the San Sebastian Stags, he had 29 points, 8 rebounds, 6 assists, 3 steals, and 2 blocks.[9] That season, he was able to win the All-Star Game MVP.[10] In a win against the EAC Generals, he had a near triple-double, with 12 points, 9 rebounds, and 10 assists.[11] After that season, he applied for the PBA Draft.[12]
PBA career
Grey applied for the 2015 PBA Draft, but his application was voided for not meeting the minimum requirement of D-League games played.[13] He then applied for the 2016 Draft, where he was taken with the 7th pick by the Meralco Bolts.[14]
Meralco Bolts
In his PBA debut, he had 11 points and 4 rebounds in a loss to the Blackwater Elite.[15] He then had a PBA career-high of 24 points against the Phoenix Fuelmasters.[16] He was able to play in the All-Star Game as a member of Gilas, leading them with 19 points against the Luzon All-Stars.[17] His time with Meralco ended when he was traded to Globalport.[18]
In his second season, Grey got to start for the Batang Pier when Terrence Romeo was injured, and scored 13 points in a loss to NLEX during the 2017-18 PBA Philippine Cup.[19] He tied his career-high in points against his former team.[20] In the Commissioner's Cup, he scored a conference high of 16 points in a win over the Columbian Dyip.[21] In Game 1 of their quarterfinals series against the Rain or Shine Elasto Painters, he scored 22 points, including a game-winning three from the corner.[22] However, they were eliminated the next game as he only scored 10 points.[23] They didn't make the playoffs for the Governors' Cup, despite making the quarterfinals the previous two conferences.[24]