By 13, he was taller than his father, former Highlanders lock Brendon Timmins.
And at 15, the year 11 Otago Boys' High School pupil is a big lump of a lad at 2.04m and 104kg.
And yesterday he was named in the Otago Nuggets squad.
He is a centre, obviously. And from all accounts the New Zealand under-17 squad member has a bright future.
He hopes to follow in the footsteps of the likes of Steve Adams and Rob Loe, and play college basketball in the United States.
Of course, Sam's priority is NCEA exams at the end of the year. And with American Antoine Tisby the starting centre for the Nuggets, Sam will have to bide his time.
''I'm only 15, so it is pretty crazy,'' Sam said when asked about his inclusion in the Nuggets squad.
''I just started going to training and scrimmaging with them and never expected to make the squad.''
The teenager has a decent sporting pedigree, on both sides of his family.
Brendon Timmins played 42 games for the Highlanders from 1996 to 2002, and 74 games for Otago from 1992-99. The durable lock also played for Southland, and is now the coach of the Zingari-Richmond premier side.
Sam's maternal grandmother, Sandra McGookin (nee Goodsir), won six national javelin titles in the 1970s and competed at the 1974 Commonwealth Games, placing sixth. Sam's grandfather, Ron McGookin, played rugby for North Otago.
