Harrison Barnes Blocks Prop is currently Over/Under 0.5 (+310/-500).
The money has been on the Under as it opened 0.5 @ -500 before it was bet down to 0.5 @ -500.
FACTORS THAT FAVOR THE OVER:
The Spurs will likely see a rise in possessions today from competing against the speediest pace-of-play road team in the NBA this year (the Toronto Raptors).