"Last season was probably my best for wickets but this season's been close," says the new-ball merchant who comes in at second change for his HBHS first XI in the second year.
The former Clive School and Havelock North Intermediate pupil suspects it has something to do with his growth spurt.
Standing at 1.8m, Greville is able to find prodigious swing in his deliveries. Throw in the factor that Cornwall Colts see him as a death bowling prospect and the picture isn't so pixelated after all.
"Usually when I get a lot of wickets in a game the ball is new," says the teenager who has been under the tutelage of his father, police officer Brent Greville, with HBHS mentors Dean Roulston and Dave Castle taking him to a different plane.
Sticking to a regimented line-and-length policy means the schoolboy makes it the batsmen's problem to become imaginative in eking out runs.
He feels the quality of batting has incrementally got better so every wicket is rewarding.
During a Labour Day weekend tournament, Greville claimed 11 scalps (tourney best) over three games, including a 5-17.
Sitting on 105 wickets in 55 appearances for Cornwall, he has claimed 13 scalps and about 10 for his HBHS first XI side who have beaten St John's College and Taradale High School counterparts and host Lindisfarne College today. He has eight five-wicket bags.
For the record, premier clubmates Jayden Wiggins (153 wickets from 133 appearances) and Jono Hall (139/124) and Lions player James Crowther (124/80) are setting the pace above him.