Portland Sea Dogs infielder Christian Koss slides into third base Thursday, advancing on an errant throw after he stole second. As a team, Portland leads Double-A baseball in stolen bases. Ben McCanna/Staff Photographer

To Corey Rosier, first base is nothing but a waiting room. A rest area on the way around the bases. If Rosier has his way, he won’t be there long.

“Every time I touch first, I’m honestly looking to run every single time. I know it’s part of my game, and how it can change the course of a game, so anytime there’s an opportunity, I’m looking to go,” said Rosier, a Portland Sea Dogs outfielder in his first full season with the Boston Red Sox organization.

Rosier leads the Eastern League with 22 steals, with teammates Ceddanne Rafaela (20 steals) and Phillip Sikes (19) right on his heels. Through Friday’s games, Portland had 96 stolen bases, leading not just the Eastern League but all of Double-A baseball. The Sea Dogs are in first place in the league’s Northeast Division.

“This group, we have a fast group of guys,” Sikes said during batting practice last week at Hadlock Field. “There’s no reason we should not lead Double-A in stolen bags.”

Last season, the Sea Dogs set the club single-season record for stolen bases with 171. This year, the team is on pace to shatter that mark, averaging more than two steals per game.

Stolen bases are up across all of professional baseball, but the pace at which the Sea Dogs and other franchises in the Red Sox farm system are stealing bases this season is notable.

Each of Boston’s four minor league affiliates has seen significant rise in stolen bases. Coming into the weekend, Triple-A Worcester has 89, second-best in the International League. High-A Greenville is third in the South Atlantic League with 78 steals, while Low-A Salem is third in the Carolina League with 94. With the exception of Portland, which finished third in steals in the Eastern League last year, the other Red Sox affiliates finished in the bottom half of their leagues in steals in 2022.

It’s the result of a concerted effort by the Red Sox to encourage prospects to be more aggressive on the bases. Brian Abraham, Boston’s director of player development, called it winning on the margins.

“We just overall want guys being aggressive, always fighting to get that extra 90 (feet),” Abraham said. “I think athleticism is important. It’s about good jumps, about reading the pitcher. Athleticism is something we value. We want guys who can provide versatility across the diamond.”

At the major league level, changes have been adopted this season in an effort to create more action. They include introduction of a pitch clock, limiting the number of times a pitcher can attempt a pickoff throw during an at-bat, and bases that are 18 inches wide rather than 15. Through Friday’s games, there has been a 46% increase in steals in the major leagues compared to games through May last season. The Red Sox had 31 steals through Friday, tied for eighth among American League teams, after stealing only 11 bases through May 2022.

The pitch clock was first used in Double-A baseball in 2015, and larger bases were introduced in the minor leagues last season.

As a team, Portland has an 81% success rate when attempting to steal this season. Eleven Sea Dogs have at least one stolen base. Christian Koss has 11 steals, Tyler McDonough has eight. Even Niko Kavadas, a 5-foot-11, 235-pound first baseman known for his power and not for his speed, has swiped a bag.

“It was definitely something that was talked about a lot in spring training, looking for every opportunity, man,” Rosier said. “Even if you get thrown out, just having that aggression and that fear in the back of the (pitcher’s) mind, I think it plays a big role.

“I’ve been seeing guys tweeting how much stolen bases are up. It definitely plays a factor into (defenses) not being able to control the run game that much. It just wreaks havoc.”

Rosier pointed at Portland’s 5-4 win in Game 1 of a doubleheader last Sunday in Hartford. Down 4-0 in the sixth inning, Rosier reached base on an error with one out, then took second base like it was owed him. That sparked a five-run rally that led to the win.

In the ninth inning of Tuesday’s 6-4 win over New Hampshire, with the Sea Dogs trailing 4-1, Sikes led off with a single and stole second, eventually scoring on a Kavadas sacrifice fly before Stephen Scott’s game-winning home run.

Putting a greater emphasis on speed and base running savvy isn’t something the Red Sox limit to evaluating players in the draft. They’ve made it a priority in acquiring players via trade, too. David Hamilton came to the Red Sox in a trade with Milwaukee in December 2021. Now playing in Worcester, Hamilton set a Sea Dogs record with 70 stolen bases last season, and entered Saturday’s games with 24 steals this year. Rosier joined the Red Sox organization in a trade-deadline deal last season with San Diego. Koss was traded by Colorado to Boston in December 2020.

Portland’s David Hamilton slides under the tag of Somerset’s Anthony Volpe for a stolen base during a game at Hadlock Field in May 2022. Hamilton, now playing for Triple-A Worcester, set the Sea Dogs’ single-season record with 70 stolen bases last season.  Shawn Patrick Ouellette/Staff Photographer

“As an organization, the last couple of years we’ve been pounding the base running. Especially here, the guys are getting it. They see the opportunities in front of them and they’re having fun with it,” Sea Dogs Manager Chad Epperson said. “We have a lot of guys who have some speed. There’s a quite a few of them in the lineup on any given night who have the green light. So unless the scoreboard tells us otherwise, they’ll always have the green light.”

Nobody used that green light more than Rafaela on Mother’s Day weekend. On Saturday, the center fielder swiped six bags, a team single-game record. On Sunday, he stole three more. Rafaela wasn’t caught stealing in either game.

“I was just getting on base and I got a chance to steal. I wasn’t really paying attention to how many bases I got. In the moment, just keep going,” Rafaela said.

The rule limiting a pitcher to just two disengagements per plate appearance, be it a pickoff move or simply stepping off the rubber, is something the Sea Dogs have taken advantage of. Once that second disengagement has occurred, it’s a bigger green light than any Epperson could signal from his post coaching third base.

“You’re sitting at a poker table, right? You look over and odds really go in our favor if you’re not successful with your pick(off),” Epperson said. “We play that game. We keep it in mind. We want that disengagement, because the odds go with us. We play a game within a game with it.”

Rafaela says that once a pitcher has used both his disengagements during an at-bat, he has to go for the steal as soon as possible.

“He tries the pickoff twice, now you have a bigger lead and a better chance to get to second,” Rafaela said.

Base running is not without risk, obviously. In Thursday afternoon’s 3-2 win over the Fisher Cats, Koss was thrown out trying to stretch a single into a double in the third inning. In the eighth, Sikes wandered a little too far from second base and was picked off. Even Rosier, the team’s stolen base leader, has been caught twice.

“I think I was safe on both of those, too,” Rosier said.