The Oakland Athletics and Baltimore Orioles are in the process of signing some of the MLB's best relievers. The A's signed a reliever away from the Kansas City Royals and the O's retained one of their own.

Ryan Madson has agreed to terms with the Athletics, according to the latest rumors. ESPN's Jerry Crasnick is reporting the deal is for three years and $22 million and is pending a physical.

Madson, 35, had a tremendous bounce back season with the Royals and won a World Series after having been out of the MLB from 2012-2014. The right-hander maintained a 2.13 ERA and 0.96 WHIP with 58 strikeouts in 68 games (63 1/3 innings).

MLBTradeRumors.com predicted Madson would land a three-year deal in the $15 million range and some experts predicted similar deals (or less), but due to the thin market for relievers he's clearly in high demand.

In Baltimore, the Orioles will reportedly retain right-handed reliever Darren O'Day, according to FOX Sports' Ken Rosenthal. The deal is for four years and $31 million and is pending a physical.

Yesterday it was reported the Washington Nationals were the frontrunners for O'Day, but Jon Heyman of CBS Sports reported earlier today that the 33-year-old was "likely" to return to Baltimore.

O'Day has spent the past four seasons with the Orioles and is 23-8 with a 1.92 ERA, 0.94 WHIP and 283 strikeouts in 273 games (263 innings). Previous rumors suggested O'Day was looking for a three- to four-year deal in the $28-$34 million range and MLBTradeRumors.com predicted he'd get $22.5 million over three years.

ESPN's Jim Bowden believed he'd sign for $21 million over three years.

However, O'Day is the best reliever in free agency this season when a number of MLB clubs are desperate for bullpen help. The Orioles did not want to repeat their offseason mistakes from last year when they let big names such as Nelson Cruz and Nick Markakis walk. They've re-signed O'day, catcher Matt Wieters and are hopeful to get back Chris Davis.

Stay tuned for official announcements regarding these signings.