0nly: I agree that in my observation, SPD is the driving factor for steals (it is a certainty for Guards). And also in my observation, ATH and DEF seem to be almost equal and both secondary to SPD where steals are concerned. Steals are obviously not the only thing that matters in playing good defense though. Opponent Shooting Percentage (OPS) and Defensive Rebounding (DR) are also key, as are other defensive 'turnovers which are not steals' (TONS).
My observation is that DEF is certainly key to lowering OPS and also increasing TONS. And ATH (along with REB) is key in DR .. so getting exactly the correct mix of the 3 (SPD, ATH, DEF) is not as straight forward as getting steals.
But, as others have said, specifically for this player on this team, the opponents quality is, IMHO, the main reason for this guy's steal totals. Certainly his outstanding ATH, average BH and PER, and what looks like a -2 setting for 3-Point shooting is going to get him a lot of free throws .. especially against inferior defensive competition.
EDIT:
Looking at this further though, I do see that Swanson did average 1.9 steals per game in your Non-Conf schedule, which was against pretty good competition. Swanson consistently had at least one steal every Non-Conf game .. and he had 3 games out of 10 with 3 (or more) steals.
So, it does seem that an extremely high ATH/DEF combo can also get you steals with speed being not so good, at least at D3. mfnmyers does sometimes get steals with his teams and average speed guards. At least steals in the 1.5-1.9 per game range.
4/9/2016 10:28 AM (edited)