Infield Fly Rule Question About Baserunners
 

Can the runners on base be forced out at their original base if the fielder catches the ball in the air and tags the base before they return to it?

No. A force out is the result of a batter becoming a runner and runners being forced to advance. The major ramification of a force out is that if the third (or subsequent out) is a force, then no runs can score.

What you have is an appeal play. An appeal is a play based on an infraction a runner did with regards to a base (missing a base, leaving too early on a catch, etc.) In many cases, a tag of the runner is not required, which is why some people mistake it for a force out.

Long and short, a runner can never be forced out at the base they occupy; only the next base.

To clarify, the runners must retouch their base after any fly ball is caught. If the defense touches the base or runner before they return after the ball is caught (touched, technically) the runner is out. This requirement is not removed because of an infield fly situation.

Matt is correct - this is not a "force out," but an appeal play.

Thanks for the replies - you answered my question.