(Pat Sullivan/Associated Press)

Manager Davey Johnson has always contended that the Nationals’ inability to hold on runners, mainly the fault of the pitchers’ slow moves to home plate, wasn’t an issue because the pitching staff has been so good at preventing runners from scoring and he didn’t want to fiddle with deliveries that have worked so well. But on Saturday, Utley stole two bases in one inning and scored on a sacrifice fly that provided a valuable insurance run in a 4-2 defeat.

On the first pitch of Ryan Howard’s at-bat, Utley tore off for second base. Catcher Kurt Suzuki bobbled the ball, but there was little chance for a play. After Howard struck out, Utley took off for third base on the first pitch of John Mayberry’s at-bat. Suzuki made a good throw, though slightly wide of the base. Regardless, Utley got a good jump both times without any contest from Burnett. Mayberry eventually lifted a ball to right field to score Utley from third base.

“[Burnett] is the consummate pitcher,” Johnson said. “He’s beating himself on it. The guy was running even before he even made a move, and he didn’t check him. That can’t happen. Those are mental mistakes, not physical mistakes.”

Including Saturday, runners have stolen six bases against Burnett, the third-most stolen bases against any reliever behind Craig Stammen (12 stolen bases allowed) and Henry Rodriguez (seven). No base runners have been thrown out with Burnett on the mound.

Following the game, Burnett was visibly upset at himself for his performance. This one moment shouldn’t overshadow Burnett’s strong season, the best of his career: he leads the Nationals in ERA (2.01) over 49 1 / 3 innings, striking out 50 batters and walking only nine in that span.

But as a team, the Nationals have been exposed on the base paths. Entering Saturday’s games, they have the second-worst caught stealing percentage in the majors. They have allowed 92 stolen bases in 107 attempts (an 86 percent success rate), second to the Pittsburgh Pirates. Since acquiring Suzuki in a trade on Aug. 3, the Nationals have allowed 15 stolen bases in 17 attempts.

“[Chase] took some gambles and went on first move and it worked out,” first baseman Adam LaRoche said. “As a team, we need to know who is capable of doing that and keep that in mind in those situations.