Entering play on Friday, the Sox had stolen 93 bases while being caught just 19 times for an 83-percent success rate.
"Well, they're smart baserunners," Farrell said. "They spend time studying the pitcher on the mound at the given moment. We've got some reminders that run through [coach] Arnie [Beyeler] at first base, to what they might trigger on as a key. They pay attention, in addition to their physical abilities. It's not an accident that they are as successful as they are."
Jacoby Ellsbury leads the way with 44 steals in 48 attempts. Shane Victorino is 17-for-20 while Dustin Pedroia is 16-for-21.
"I think if you're north of 75 percent, you stay the course," Farrell said. "When an individual falls below it, then you've got to pull back in."
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.