Baltimore was reportedly shopping their closer for salary relief in recent weeks. Johnson, 30, is projected to earn more than $10 million in 2014 according to Matt Swartz of MLB Trade Rumors, so the Orioles are saving a nice chunk of change with the trade.
In 74 games this past season, Johnson managed to lead MLB in both saves (50) and blown saves (nine). He had a 2.94 ERA (143 ERA+) and a 3.11 K/BB in 70 1/3 innings. Johnson also led MLB with 51 saves in 2012 and saves are an easy way to earn a huge salary through arbitration. The sinkerballer is due to become a free agent next winter.
Weeks, 26, hit .303/.340/.421 (110 OPS+) in 97 games as a rookie in 2011 but he has been unable to build on that success. He put up a .221/.305/.304 (73 OPS+) line in 2012 before spending most of 2013 in Triple-A. Rickie's little brother did manage a .271/.376/.369 line in 130 minor league games this past season.
The trade fills a need for both teams. The A's lost closer Grant Balfour to free agency while the O's have a long-standing hole at second base due to Brian Roberts' continued injury problems. Baltimore likely views Weeks as a change of scenery player.