The A's beefed up their bullpen Saturday, four days in advance of the MLB trade deadline. 

Oakland acquired left-handed reliever Jake Diekman from the Kansas City Royals in exchange for prospects Ismael Aquino and Dairon Blanco, the team announced.

ESPN's Jeff Passan first reported the deal, and MLB Network's Jon Heyman first reported on the return. 

The San Francisco Chronicle's Susan Slusser reported the Royals were interested in outfielder Jameson Hannah, who Baseball America ranks as the No. 7 A's prospect and was not included in the deal. Blanco was ranked as the No. 26 A's prospect by Baseball America. 

Diekman, 32, signed a one-year contract -- with a $5.75 million mutual option for 2020 --  with the Royals this offseason. He has made 48 appearances for Kansas City in 2019, posting a 4.75 ERA, 1.34 WHIP and striking out 63 batters in 41 2/3 innings. Diekman's fielding independent pitching (FIP) this season is 3.36, and opposing batters have a .330 batting average on balls in play (BABIP) against him. 

Moving from hitter-friendly Kauffman Stadium to the pitcher-friendly Coliseum should help Diekman. Passan reported that "a number of teams" explored trading for Diekman, and The Washington Post's Jesse Dougherty added that the Washington Nationals "kicked the tires" on acquiring Diekman.


Diekman is not the first pitcher the A's acquired from the Royals this season. Oakland traded minor league infielder Kevin Merrell to Kansas City for Homer Bailey on July 14. 

[RELATED: What Braden wants from A's rotation before deadline]

The A's might not be done dealing yet, according to The Athletic's Ken Rosenthal.

Oakland entered Saturday a half-game back of the AL's second wild-card spot. The A's clearly are betting on Diekman to help them bridge that gap.