The rule doesn’t specify a certain distance, but the fielder must make a legitimate attempt to retire the runner at third or it would be a balk. A feint to third is still allowed if the pitcher steps off the rubber first. Please refer to rule 9-3-c....Note: If the pitcher throws to the first or third baseman who is playing off the base, a balk shall not be called if the fielder moves toward the occupied base in an attempt to retire the runner.