More than halfway through the season, it's an approach that has yielded results for the team with the best record in the American League. No team in the AL has stolen more bases (73) and no team is successful a higher percentage of the time (82 percent) than Boston, which also owns the highest-scoring offense in baseball.
But sometimes -- like during the Red Sox's 5-2 loss to the Yankees on Saturday -- the aggressiveness can backfire, and when it does, it can cost them the game.
The Sox didn't have many opportunities Saturday, but they ran themselves out of many of their most promising chances. Three runners were thrown out in the game, including two at home plate, squandering some of the few chances they had to put runs on the board.
"It's a fine line," manager John Farrell said. "Game situation is going to dictate most of it, if not all of it. It worked against us a couple times today."
Daniel Nava was thrown out twice, including once at home. The first instance came in the game's opening frame when he tried to score on David Ortiz's single.
Nava stumbled rounding third, giving Yankees left fielder Vernon Wells more than enough time to fire the ball to catcher Chris Stewart and get Nava with several steps to spare.
"You've got to send someone in that situation with two outs, and he made a good play, made a good throw and, unfortunately, today was just a rough one on the bases for me today, so I'll learn from it," Nava said.
Nava's footing might have failed him in the first, but later in the game, Nava said his brain was to blame. Trailing by two in the eighth, Dustin Pedroia popped out behind home plate. Stewart leaned into the crowd to make a tough catch, but Nava -- even though Ortiz was coming up to the plate as the game's tying run -- tried to tag and advance.
Stewart fired to second in time to catch Nava for the third out of the inning and end the last threat the Red Sox mounted in the game.
"Right before the play happened, I was actually told don't go anywhere, and then I just stopped thinking when the ball was hit in the air," Nava said. "That's unfortunate, because late in the game, you need to be on top of stuff, and that was just one of those times when I just wasn't on top of what I should have been on top of."
Added Farrell, "Down two with David on deck, again, overaggressiveness on that part."
In the fifth, the Red Sox had runners on second and third with two outs, but when a pitch slipped by Stewart, Mike Carp was caught trying to score from third, ending yet another threat.
In a close game against a division rival, the mistakes added up.
"We had a couple opportunities and we didn't run the bases so well today, myself included, and it cost us the ballgame," Carp said.
One game won't change Boston's approach, though. Farrell firmly believes in a healthy amount of aggression, and unless the mistakes become a pattern instead of an anomaly, Boston will continue to push the limits on the bases.
"We run the bases well," Carp said. "We've done a good job all year moving guys, shuffling first to third and scoring on base hits from second. Just one of those things. It happens and you don't want it to happen very often. Just go back out there tomorrow and get after it."