There are a few key rule changes coming to Major League Baseball this season, but one in particular already is throwing players for a curve.

Spring training games underway in Florida and Arizona have featured a new pitch clock, which gives pitchers a set amount of time before they have to throw the ball.

The timer is set to 15 seconds if the bases are empty or 20 seconds if there are runners on base, and the hitter has to be in the batter's box with eight seconds left on the clock.

MLB officials say the pitch clock can help reduce the length of games, which have averaged more than three hours long in recent years. But the new rule has drawn some criticism, and over the weekend it caused bewilderment on the diamond.

On Saturday, during a spring training matchup between the Atlanta Braves and the Boston Red Sox, Braves hitter Cal Conley was called out for failing to get into the batter's box on time. The game — which was in the bottom of the ninth inning with a full count, two outs and the bases loaded — ended in a tie. Conley reacted with shocked laughter.

The pitch clock isn't the only new rule popping up this season.

First, second and third bases have grown in size from 15 inches square to 18 inches square, which the MLB says will reduce player injuries. The league is also requiring two infielders on each side of the second-base line before a pitch is thrown, preventing them from crowding one side or another in a defensive maneuver known as the "infield shift."

League officials say the rule changes didn't come out of left field but rather were developed in response to feedback from players and umpires, and were first tested in the minor leagues.

"These steps are designed to improve pace of play, increase action, and reduce injuries, all of which are goals that have overwhelming support among our fans," MLB commissioner Robert D. Manfred, Jr. said in a statement in September, when the new rules were approved.

"Throughout the extensive testing of recent years, Minor League personnel and a wide range of fans – from the most loyal to casual observers – have recognized the collective impact of these changes in making the game even better and more enjoyable," Manfred added.

For example, last year in the minor leagues the pitch clock helped reduce the average length of a game by 25 minutes, and the larger bases led to a 13% reduction in "injury events" near the bases, the MLB said.

That teams will be able to get used to the new rules — particularly the pitch clock — during spring training. And despite the pushback, some pitchers have suggested the new timer may actually give them an advantage.

"I can work extremely quickly, or I can work extremely slow," New York Mets star pitcher Max Scherzer told reporters after his first spring training start. "There is another layer here to be able to mess with the hitter's timing." [Copyright 2023 NPR]