Red Sox reliever Garrett Whitlock heads to IL with pectoral strain

The Red Sox are placing reliever Garrett Whitlock on the 10-day injured list due to a right pectoral strain, manager Alex Cora told reporters (including Alex Speier of the Boston Globe). Cora stressed that the club doesn’t view the injury as overly serious but wants to be cautious to not aggravate the issue. He didn’t rule out the possibility of Whitlock returning after a 10-day minimal absence.

Even if Whitlock is able to make it by the middle of next week, his loss will still be a tough blow for a Boston team in a tightly contested wild-card race. The Red Sox enter play Tuesday up a game and a half on the Blue Jays for the top wild-card position in the American League. The Yankees are only half a game back of Toronto for the league’s final playoff spot, and the A’s and Mariners are still within range themselves.

Whitlock has arguably been Boston’s best reliever this year, an improbably fantastic outcome for a Rule 5 draftee. Plucked from the Yankees’ system last winter, the right-hander has tossed 72 1/3 innings of 1.99 ERA ball across 45 appearances. He’s benefited from a bit of good fortune to post such a strong run prevention mark — particularly with regard to stranding baserunners — but there’s little question Whitlock has had a strong year. He’s got better-than-average strikeout (26.8%), walk (5.8%), ground-ball (49.5%) and swinging strike (12.8%) rates.

That continued strong work has unsurprisingly gained Whitlock more important opportunities as the season has gone on. After deploying him in mostly mop-up situations early in the year, Cora has increasingly leaned on Whitlock in higher-leverage game states over the past couple months. The 25-year-old has continued to perform well in those key spots, holding opponents to a .151/.220/.283 line over 59 plate appearances deemed “high-leverage” by FanGraphs. With Whitlock down, Hansel Robles, Matt Barnes and the resurgent Garrett Richards look likeliest to shoulder the most important innings late in games.