Rick White, the president of the Atlantic League and a former M.L.B. official, said the changes are intended partly to increase safety and speed up games. But baseball’s overriding goal is to combat the inertia that often dominates games in the majors, where strikeouts have increased every year since 2006 and stolen bases are at their lowest rate since 1971.

“The one rule I’m seeing that has the most effect is the ‘step off or else you’re balking’ rule,” said Mauro Gozzo, the New Britain Bees manager and a former major league pitcher. “It takes the lefty pickoff move away. It takes away the inside move to try to pick off a runner or keep him close at second. Anybody with speed has the ability to get a better jump, so there’s more risk-taking at stealing bases.”

As for stealing first base, hitters are still learning. The Bees’ Mike Carp, who won a World Series ring as a reserve for the Red Sox in 2013, said remembering that rule can be tricky.

“You’re used to playing the game one way your whole life, and when they throw in these little changes, it’s different — especially stealing first base,” he said. “I can see how that might come into effect late in the game, but you’re not thinking that in the box. The ball gets by, you’re locked into your next pitch.”

Carp said he does not notice the larger size of the bases while running, but he can tell up close — and when a routine grounder clipped a corner of the bag recently and squirted away for a hit. The new bases are three inches closer down the line, and four and a half inches closer between first and second and between second and third.

“Bang-bang plays that occurred last year are probably being called safe today,” White said. “Stealing and getting more running in is one of the objectives baseball has. I think over time there will be a subtle but discernible effect.”