Interference

[joemoore]

Was the runner already out and then flagrantly interfered with the fielder making a chance at a double play?

9.01(d) gives the umpire sole discretion in ruling on unsportsmanlike conduct.

I would imagine a runner obstructed from reaching a base, such as a catcher blocking the plate (with or without the ball) would not be ruled unsportsmanlike. I can't see how a third baseman blocking third base would be different.

What I do notice is that fielders in MLB do not block any base except home. They will usually straddle or play off to the side of the base. If a runner put his shoulder into a shortstop straddling second on a tag for a steal attempt, that might be unsportsmanlike.

I can't see where any other rule would apply.