Over the season’s first 100 games, the Yankees raced to the largest divisional lead in the major leagues with a sense of urgency, impressively withstanding injuries to critical players while wringing the most out of their depth.

After a forgettable Western trip and two tough losses to the Boston Red Sox last weekend, however, there was a sense that the Yankees might be growing complacent in their perch atop the American League East.

On Monday, they lost to the Baltimore Orioles, 5-4, allowing a rookie pitcher to subdue them for nearly seven innings while failing to come up with enough clutch hits in the end. It was the Yankees’ eighth loss in 11 games.

And the slide could get more slippery with another injury: first baseman Mark Teixeira left the game in the seventh with an injury to his left wrist after diving for a ground ball.