As they climbed their way to within three games of the second American League Wild Card spot over the last week, the A's did so on the back of their bullpen, which compiled a 2.45 ERA over 29 1/3 innings to earn MLB Bullpen of the Week presented by The Hartford for the period of July 9-15.
As part of The Hartford Prevailing Moments program, each Monday throughout the 2018 season, MLB.com is honoring the MLB Bullpen of the Week presented by The Hartford. An industry-wide panel of MLB experts, including legendary stats guru Bill James, constructed a metric based on James' widely renowned game-score formula, to provide a weekly measurement of team-bullpen performance.
Here's how the Bullpen Rating System is compiled for each week. For reference, a weekly score of 100 is considered outstanding:
• Add 1.5 points for each out recorded
• Add 1.5 points for each strikeout
• Add 5 points for a save
• Subtract 2 points for each hit allowed
• Subtract 4 points for each earned run allowed
• Subtract 2 points for each unearned run allowed
• Subtract 1 point for each walk
• Subtract 5 points for a blown save
The Oakland bullpen paced the Majors with a score of 112.5. The second-highest score was 101.5, by the Dodgers.
The A's went 5-2 last week, riding series wins over the defending champion Astros and crosstown rival Giants, positioning them to within earshot of a postseason spot heading into the All-Star break.
Blake Treinen, who with second baseman Jed Lowrie will be Oakland's lone representatives at the All-Star Game presented by Mastercard on Tuesday in Washington, picked up a pair of saves to bring his season total to 24, which trails only Edwin Diaz (36), Craig Kimbrel (30) and Albertin Chapman (26) in the AL. Even with a blown save against the Astros on Tuesday, Treinen's 0.96 ERA for the season leads all MLB relievers.
The unexpected: Within Oakland circles, Lou Trivino has established himself as one of the Majors' top setup men. But among a wider audience, the late-blooming 26-year-old is a relatively unknown rookie. Trivino has been slicing through opposing lineups with high-90s velocity to the tune of a 1.25 ERA, the fifth-best among relievers in all of baseball.

Last week, he continued his dominant stretch with four hitless outings over a combined six innings, with eight strikeouts among 20 batters faced. Trivino has now thrown a scoreless outing in 32 of his 36 appearances, including 10 straight dating back to June 27. His 1.25 ERA ranks fifth-best among all MLB relievers.
How they prevailed: Put simply, consistency. Treinen's one blemish, which led to Tuesday's 6-5 loss to the Astros in 11 innings, only consisted of one earned run, one hit and one walk. But the A's also got scoreless appearances 19 times from a combination of Treinen, Trivino, Yusmeiro Petit, Ryan Buchter, Santiago Casilla, Chris Hatcher, Ryan Dull and Emilio Pagan.