- Bats Left, Throws Left
- Height 6' 1", Weight 176 lb.
Prioul allowed four runs in eight innings and had no decisions in the 2015 European Junior Championship.  He made his Division I debut, with a 4.34 ERA for the champion Rouen Huskies despite 23 BB in 18 2/3 IP.  He allowed one run in 1 1/3 IP in the 2016 CEB Cup.  In the Division I that year, he had five saves and a 2.11 ERA with no wins or losses. He again was wild (19 BB in 21 1/3 IP) but gave up just 9 hits for a .127 opponent average. Rouen again won it all. The teenager led the league in saves, two ahead of Anthony Piquet and Jimmy Jensen. 
He debuted for France's senior team in the 2016 World Baseball Classic Qualifiers, making his lone appearance in France's first win ever in a World Baseball Classic qualifier. He relieved Keino Perez with a 5-1 lead over Spain in the 6th, the bases loaded and two outs. Iker Franco drew a pinch-hit, four-pitch walk and Prioul was replaced by Samuel Meurant, who had made his French team debut before Prioul was born.  He was rocked for Rouen in the 2017 European Champions Cup (4 R, 3 ER, 3 H in 1 IP) to post their highest ERA.  He had a 4.76 ERA in the 2017 U23 European Championship, walking 9 in 5 2/3 IP. 
The youngster moved to the rotation for much of 2017, going 6-0 with a 1.52 ERA. He walked 32 in 41 1/3 innings while giving up just 21 hits for a .165 average. He was among the league leaders in ERA (3rd, behind Dylan Barrow and Owen Ozanich), opponent average (3rd, behind Barrow and Keivy Rojas) and wins (tied for 3rd, behind Jean Granados and Ozanich). Rouen won a third pennant in a row.  In the 2018 European Champions Cup, he was much better than the prior year (0-1, 2.35), losing to Diegomar Markwell and the champion Curaçao Neptunus.  He was 1-0 with two saves and a 2.96 ERA for Rouen in the 2018 regular season, pitching both in relief (7 G) and as a starter (3 G) for the victors. He was 8th in ERA (between Meylian Marin and Matthieu Brelle-Andrade), second in opponent average (.183, .004 behind Yorfrank López) and tied Luis de la Rosa for the most saves. 
After long-time Rouen anchor Ozanich left to play in Italy in 2019, Prioul was again returned to the rotation. He faced Ozanich and Parmaclima in the 2019 European Champions Cup and was outmatched (12 H, 12 R in 3 IP before Quentin Moulin relieved) in a blowout loss.