Rockies reliever Rafael Betancourt continues to struggle at AT&T Park

Rafael Betancourt statistically is one of the best relievers in Major League Baseball over the past decade.

No, really -- he is. Since arriving in the majors in 2003, Betancourt ranks highly in many categories among relievers with at least 500 innings during that time. He has the third-lowest walk rate, third-best K-BB percentage, fifth-highest WAR -- you get the picture. Betancourt has made a living off of making hitters look bad, and he's done it for a lot of years in a lot of places.

But one of those places, it seems, isn't San Francisco.

Betancourt entered Saturday with a 5.14 career ERA and having allowed Giants batters to hit .291/.328/.564 against him in 62 plate appearances at AT&T Park. Those numbers are worse, now; the Giants scored three runs with Betancourt on the mound in the bottom of the seventh inning, turning a 5-4 lead for the Rockies into a 7-5 deficit. Catcher Andrew Susac delivered the big blow, lining a bases-clearing double down the left field line after the Rockies intentionally walked Buster Posey with runners on second and third and first base open.

It's almost a given that Betancourt is good for one meltdown by the bay every season. Let's take a look back:

Aug. 30, 2009: Betancourt allowed a grand slam off the bat of Edgar Renteria, turning the tables, giving the Giants revenge on the Rockies for Ryan Spilborghs' memorable walk-off grand slam the previous week.

May 6, 2011: The Rockies held a 3-1 lead before Betancourt surrendered a game-tying, two-run double to Nate Schierholtz, The Giants scored on Felipe Paulino in the 10th inning to walk away with the win.

Aug. 12, 2012: Hunter Pence could not hit a beach ball after the Giants acquired him from the Phillies -- until the eighth inning of this game, that is. Betancourt, called upon for a four-out save, allowed a game-tying sacrifice fly before Pence launched a go-ahead, three run shot, eventually giving San Francisco a 9-6 victory.

May 25, 2013: After Troy Tulowitzki (Mr. Clutch) hit a go-ahead homer in the top of the 10th, Betancourt issued a rare leadoff walk to Brandon Crawford in the bottom half of the frame. He paid for it dearly when Angel Pagan launched a ball into triples alley, using his speed to come all the way around and score on a walk-off, inside-the-park home run.

And now, add June 27, 2015 to that list. After his latest gut-wrenching performance at AT&T Park, Betancourt owns a 6.75 ERA in 2015. He's been a bit unlucky; for instance, he entered the game with his normal brand of ridiculously impressive strikeout and walk rates -- the latter of which won't look as good now as a result of two intentional free passes. But the 40-year-old's command of the strike zone isn't quite what it used to be. That will be a thing to watch going forward as the Rockies continue to navigate through what has been an overall poor performance from the bullpen over the last two months.