How could instant replay be expanded in baseball?

Major League Baseball commissioner Rob Manfred set off a firestorm of criticism and concern when he stated in an ESPN interview that he favored the use of a pitch clock and would consider banning defensive shifts. Lost in that conversation was a positive reaction to the possibility that baseball could once again expand the use of instant replay.

Manfred said that the implementation of replay to cover almost any play in the field, or at any base, had been a smashing success. When pressed about further expansion of replay, he said "possibly." What could be covered that is not already reviewable if the use of replay were to be expanded again? The vast majority of plays, once the ball is put into play are reviewable. A few possibilities come to mind:

A "tag up" play, where the runner tags up to advance on a fly ball, is currently not reviewable. In a game against Detroit in September, the  Royals' Salvador Perez was called out on a tag up after the replay was shown on the scoreboard during a time out. This play may have been the difference in the Tigers winning the AL Central Division. A review would have gotten the call correct every time.

A ball that bounces off the batter's foot after being hit is not reviewable, as the Cardinals know from their playoff game against the Dodgers. Cardinals second baseman Kolten Wong was thrown out at first after fouling the ball off his foot. There is no reason that plat should not be reviewed.

A "phantom tag" at second base on a double play is known as the "neighborhood play." Players are opposed to the review of plays where a runner is called out at second base when the fielder actually left the base before receiving the throw. The concern is that players would be forced to stay on the bag longer to be sure that an out is recorded, putting them at increased risk for injury due to more collisions with the baserunner.

The players' concern could be alleviated by adjusting the rules to prohibit a runner from intentionally taking out the fielder to break up a double play. A fielder who crosses second base at the back of the bag would be off limits to a sliding base runner in the same way that a catcher fielding the ball at home is now protected by rule from a runner who intentionally crashes into him to break up a play at the plate.

Check swings are another area where replay is not used. There are many controversial calls on check swings. A batter may be called out when he didn’t go around, or not rung up when he did go around with his swing. Appeals could be used in any count, or limited to just those with two strikes on the hitter. One method of enforcement could be placing sensors in the appropriate part of home plate that would detect when a bat passes through the sensor, signaling that the hitter went too far when checking his swing.

Balls and strikes are an area where replay is not used for fear that there could be so many calls appealed. While this is probably the last area that baseball wants to get into in terms of appealing calls -- and the last area where umpires want to be questioned -- it is certainly the area that has the greatest potential for the expanded use of replay technology.

If the pace of game is an issue to the point where baseball is considering installing pitch clocks, then replay needs to be truly instant. The system eliminates the delays due to arguments on the field, and most reviews are completed within a couple of minutes, which is a tolerable delay in the interest of getting the call right.

One has to question why replay reviews have to come as a result of a manager’s challenge rather than at the discretion of a video review umpire either on site or in a remote location. As long as the system relies on a manager’s challenge, most would like to see the decision on whether or not to challenge made quickly. If baseball is going to stick with using managers' challenges, then why are they limited to just two challenges per game, even if their challenges are upheld?  Why should there be a limit on the number of correct calls in a game?

If there is anything that bothers fans about instant replay, it is those times when the replay review isn’t exactly instant. When a manager comes out of the dugout only to stall for a moment and then heads back to the dugout without challenging, it is frustrating. Most observers tend to think that whole charade could be eliminated from the game.