Batters in the Atlantic League will get the chance to steal first base in a new series of experimental rules announced Thursday.

As the independent minor league prepares to expand the use of "robot umpires" leaguewide, Major League Baseball and the Atlantic League added four more rules to the second half of the season.

Batters may try to steal first base on any pitch that was not caught in flight. It expands the traditional dropped third strike rule to all pitches, and batters can be thrown out if they try to run.

Other rules being added:

• One foul bunt is allowed with two strikes before it becomes a strikeout.

• Pitchers are required to step off the rubber to try a pickoff.

• A relaxation on check swings to be more batter-friendly.

In February, the Atlantic League and MLB announced a three-year partnership that allowed the league to serve as a testing ground for experimental playing rules and equipment. In March, they announced the first set of rules, including the TrackMan radar system for calling balls and strikes, the ban of the shift and a three-batter minimum for pitchers.

"We have seen a tremendous amount of interest in these initiatives from our players, coaches and fans throughout the first half of the season," Atlantic League president Rick White said in a statement. "We look forward to working further with Major League Baseball and observing these additional rule changes in action throughout the remainder of the year."

The TrackMan system was used for the first time in the Atlantic League all-star game Wednesday. Plate umpire Brian deBrauwere wore an earpiece connected to an iPhone in his pocket and relayed the call upon receiving it from a TrackMan computer system that uses Doppler radar.

White said the system will be implemented leaguewide over the next few weeks.

Umpires have the ability to override the computer decision.