Joe Girardi wasn't exactly the most popular man in the Bronx this past weekend as the Yankees dropped their first series since June and saw their AL East lead drop to 1.5 games over the retooled and surging Toronto Blue Jays. Girardi took heat for a few of his pitching calls, namely using rookie Branden Pinder against the heart of the Jays' order in the tenth inning on Friday night and leaving Ivan Nova in with the bases loaded in the sixth on Saturday in his first 100-pitch outing of the year. Both decisions ended with balls in the seats that propelled Toronto to victory, but for Girardi, these kinds of moves are part of a big picture approach that isn't going to change.

With question marks abound in the Yankee rotation, the team has come to rely heavily on a bullpen that's fortuitously been among the best in baseball. As a group, Yankees relievers are leading the majors in fWAR at 4.5, while running second in strikeouts-per-nine at 9.93, seventh in wins with 19 and seventh in ERA at 3.24. They're winning with a strategy similar to the one that carried the Kansas City Royals to last year's World Series–starting pitching that's good enough to keep games manageable followed by lights out late relief that turns leads into wins and close contests into favorable affairs. But one thing about that approach is that, for it to work out long-term, it requires restraint. Girardi's forced to walk a difficult tightrope between using his big guns often enough to pile up wins and making sure they're rested enough to be healthy and effective all year.

Before the Friday loss, former Yankee broadcaster Jim Kaat had some concerns over heavy use of Yankee relievers, particularly Dellin Betances and Andrew Miller, as he told the New York Post's Justin Terranova.

"They've done it with this formula so far, but now the last two months those relief pitchers are going to need some time off. They need to start getting [other] guys into games and giving these guys a breather. I don't think you can keep calling on that bullpen night after night through the end of September and not have those guys a little worn down at the end of the year."

Let me caveat this by stating that Kaat is my favorite color commentator of all time. He's always had a great non-sensationalist understanding of the game, and he knew how to jab Michael Kay at just the right times long before Paul O'Neill did. That said, Jim's way off base here, having not followed the Yankees on an everyday basis in some time. The Yankees' top relievers aren't getting overused because Girardi's done a great job making sure they aren't.

It's true that Yankee relievers as a whole have been worked a lot - their collective 352.2 innings thrown are top ten in the sport and second among good teams. But through 110 games, with just under a third of the season to go, only one individual Yankee is in the top 50 in relief innings. Betances has thrown 57.1 innings, which puts him on pace for around 84, but that's six fewer than last year's total. Miller, thanks to the time he missed with a strained forearm, is only at 38 innings over 38 appearances so far and won't come close to last year's marks of 62.1 and 73. Adam Warren is more of a worry since he spent most of the first half starting, but he's only been used on back-to-back days twice since rejoining to the pen. The 101.1 innings he's thrown so far are nowhere near his 2012 career high of 155 and could even allow for a return to the rotation. Justin Wilson and Chasen Shreve, at 40.2 and 43.2 innings are also on pace to fall well short of their personal highs as relievers–73.2 in 2013 for Wilson and 76.1 last year for Shreve.

That brings us back to Girardi's role in this weekend's losses. Pinder's fastball may hit the high 90s, but Jose Bautista and Edwin Encarnacion are tough draws for a guy with 14 innings of MLB experience. Still, Warren had thrown 41 pitches two days prior and using Miller for a second inning on a back-to-back would have probably taken him out for the rest of the weekend.

Should the call have gone to Shreve, who's thrown only eight innings since the All-Star break? Maybe. Should Warren have relieved Nova a batter sooner on Saturday? Probably. Unlike Joe Torre, though, who saw every game as a must-win and middle relievers as burnable commodities, Girardi doesn't manage one day at a time and has always had a willingness to lose battles to win wars. That means the Pinders of the world will get opportunities in big spots in a Girardi bullpen, just as he got another one in a close game Sunday. The same will hold true for Jacob Lindgren, Danny Burawa, Nick Rumbelow and others when they eventually get their turn. That approach has led to some frustrating losses, but also some important discoveries that may not have been found in the past.