Erisbel Arruebarrena was limited to pinch-running duties Wednesday because of a shoulder injury. (Getty Images)

In the 10th inning, when A.J. Ellis drew a one-out walk in a tie game, many of you chimed in on social media wondering why Don Mattingly didn’t pinch run for the slow-footed catcher.

Mattingly did use a pinch runner eventually, when the bases were loaded with one out. Erisbel Arruebarrena took Ellis’ place at third base, and barely had to move as Adrian Gonzalez and Juan Uribe struck out.

Why didn’t Arruebarrena pinch run for Ellis earlier?

This was Mattingly’s response: “I don’t think he scores (on the single by Yasiel Puig) but we talked about it before the inning ended. It’s two more players in the 10th (inning). It didn’t change anything. He wouldn’t score on that ball. Once we get him to third it’s like ‘OK, now we absolutely have to throw all our players out there.’ ”

That’s one man’s opinion but Mattingly has a point. Puig and Dee Gordon — who were both unavailable to pinch run in that situation — were probably the only two players with the speed to challenge Jayson Werth‘s arm on that hit to shallow right field. That Werth bobbled the ball before throwing home only made the decision look that much more regrettable. If Werth fields the ball cleanly, third-base coach Lorenzo Bundy sends the pinch-runner, and Werth throws a strike to home plate in plenty of time to tag the runner out, we’re asking Bundy about his decision after the game. Not Mattingly.

Still, it’s usually sound strategy to pinch run for your slowest player. Mattingly thought about it. He ultimately decided not to. Maybe it cost the Dodgers a win, maybe it didn’t.

The real story in all of this was revealed a bit later in Mattingly’s postgame press conference: Arruebarrena can’t swing a bat because of an injured shoulder. This is the first we’ve heard of the injury; the rookie shortstop had a hip injury in July.