A.J. Griffin's age, size, and measureables are favorable for the Spurs
Assuming Griffin does declare for the 2022 NBA Draft, he will be one of, if not the youngest player in his class, as he'll still be 18 years old on draft night. If the Spurs do truly intend to go through with a full or close-to-full rebuild, which the selection of Josh Primo may have hinted at, then continuing the trend of selecting talented young players and banking on their development would be in the team's best interest.
While there are certainly other young players to be had in this draft, though, Griffin shows some flashes of exactly what the Spurs need on the court, which I'll speak on later.
When looking at a player's fixed attributes, taking their age into account is only a piece of the puzzle, though. Griffin's physical profile is what is debatably most eye-catching about him. At his young age, he stands at roughly 6'6" to 6'7" (depending on where you look), and weighs about 222 pounds, according to ESPN. For being only 18 years old, that's about as NBA-ready of a body that a young wing player could have.
To go along with his already big frame, Griffin also reportedly had a seven-foot wingspan by the time he was only 15 years old, which he said is "really helpful to [his] defense." Griffin naturally plays at the small forward position for the time being, but he certainly has the size and length that would be necessary to slide in rotations as a small-ball power forward spot. More ideally, though, Griffin growing a few more inches is still in the realm of possibility.
Regardless of position, though, Griffin can come into the NBA and solely focus on developing his skills on both ends of the floor as opposed to developing those along with his body. In a developmental system like that in San Antonio, coming in with such an NBA-ready body could be tremendously advantageous, to the point that he could find himself in the Spurs' rotations sooner rather than later.