Bullpen of the Week: Rays

The Rays went 5-1 last week to improve their season record to 42-41, winning series against the Astros and Nationals. The Rays' bullpen has been a big factor when the club has had success, particularly since manager Kevin Cash began implementing the "opener," an unorthodox practice in which a reliever pitches the first inning in certain games.
Rays relievers combined to post a 1.38 ERA over 26 innings, earning MLB Bullpen of the Week presented by The Hartford for the period of June 25 to July 1.
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 Rays' bullpen led MLB with a score of 105.5. The Mariners were second with a score of 89, followed by the Phillies at 86.
Right-hander Chaz Roe tossed 2 1/3 hitless innings during the week, and rookie right-hander Diego Castillo continued to impress with 4 2/3 strong frames, in which he was charged with one run on one hit, walking one and striking out four. His ERA on the season is 1.80 in 11 appearances.
In the two games during the week that the Rays used an opener, Ryan Yarbrough gave up one run over 6 1/3 innings in relief of Ryne Stanek against the Astros last Thursday, and Vidal Nuño gave up one earned run over 4 2/3 innings following one inning by Stanek against Houston last Saturday.
The unexpected: Rays starter Wilmer Font cruised through five scoreless innings while facing Houston last Friday, but he came out of the game in the sixth due to a right lat strain after he walked Jake Marisnick and fell behind against Alex Bregman to open the inning. With the Rays leading, 3-0, Cash summoned Castillo out of the bullpen.
How they prevailed: Though Castillo surrendered a two-run homer to Bregman, he retired the next six batters he faced in order before giving way to Roe, who tossed a perfect eighth. Sergio Romo came on in the ninth and worked around an Evan Gattis single to close out the 3-2 victory.