Batter singles to right field. Rounds first base and attempts to go to second but runs into first baseman who is clearly in the baseline. Collision occurs and runner continues to second, expecting an obstruction call. He is thrown out. Umpire says no obstruction because runner “intentionally” ran into first baseman even though he was in the base path. What is the correct call?

1.48 • OBSTRUCTION
Obstruction is the act of:
B. A fielder who is not in possession of the ball nor in the act of fielding a batted ball who impedes the progress of a runner or batter-runner who is legally running bases

Dbax.. unfortunately an OBS call is the judgment of the umpire .. and remember with a runner "rounding" 1B there is no actual baseline.. some runners cut the bag sharply while others make a BIG turn going toward 2nd not actually seeing the play makes it hard to give a "correct call"

The fielder was not in possession of the ball and not in the act of fielding it. So the question is, is obstruction negated if the runner intentionally runs into the fielder?

!st Baseman impedes the runner it's an out if I am umping. As an Ump we it's difficult to judge intent.

Based on the fact that it is a judgement call, I believe most of us would have granted the base but possibly it was intentional so maybe a good call by the ump. I believe that is why mechanics are very important and if I see contact which I deem to be non intentional, arm goes out and that signals to the runner that I have noted obstruction. If I am running and that happens to me, it's the first thing I look for before continuing onto the next base. Sadly I have been called out when I felt there was obstruction but either umpire didn't see it or possibly believed it was intentional.

As BJ correctly stated it’s primarily an umpire judgement call. Basic Rule of thumb is if a fielder is not attempting to field a ball the runner has the right of way. If a runner is somehow hindered or impeded by a fielder its obstruction. While there is no real base path from say, first to second, a runner cannot deliberately go way out his or her way in an egregious manner and bump into a fielder simply trying to draw an obstruction call.
It’s a judgement call by the umpire.

FOFO, why would the runner be out if you are umping?

Still surprised that after playing first base for many years, players still don't take a few steps toward the pitching mound while watching the batters hit in the OF.

I agree with the first two posts by Dbax and BJ, the rule is in place for obstruction for impeding a runner by a fielder without the ball or a play on the ball. How does this particular umpire determine that the runner intentionally ran into the fielder? when 1st baseman was in the path of the runner turning a single into a double?

If it was intentional the runner should also be ejected from the game as he has an obligation to avoid any contact with a fielder.

Unfortunately, many umpires "look" for any reason to get that out, which helps them speed up the game. We all recognize those umpires and it takes away from the game. Every close force play "seems" to always be called an out.

Good umpires get appreciative remarks from both teams after the game, winners and losers. Bad umpiring results in discussions like this one.

FOFO, I share Dbax’s sentiment. Perhaps you meant otherwise but are you saying that a runner rounding first possibly looking to go to second is out if he’s impeded by the first baseman?