Can a first basemen interfere with a runner if play is at first base?

There are two situations when a baseman can tag the base for an out.

The first is the force out. A force out happens when a baseman tags the base of the only possible location for the runner. For example, if a batter hits a ground ball to the first baseman, the first baseman only needs to tag first base because it is the runner's only possible destination. Also, if there was a runner on first base and a ground ball was hit, there would be a force out at both second and first base because they runner on first base would be forced to progress one base. With a man on first and second base, you can force at first, second and third, and with the bases loaded, there is a force at every base. If there is a runner on second and/or third, but not first, the runners are not required to progress one base, so there is only a force at first.


The second is on the fly ball. If a fly ball is caught, a base runner must touch the base again ("tag up") before moving on to the next base. If they do not tag up after the ball is caught, the baseman at the base from which they left can tag that base for the out. For example, if there is a runner on first base and the batter hits a fly ball, and that ball is caught, the runner must touch the base after the ball is caught before he can leave for the next base. If he doesn't touch the base after the ball is caught, the baseman only need tag the base while holding the ball for the out.