UPDATED 8:53 p.m. 12/2/2013
Ken Rosenthal of FOXSports.com reported via Twitter:
— Ken Rosenthal (@Ken_Rosenthal) December 3, 2013
Johnson is a major addition for the A’s, who opted not to extend a qualifying offer to free agent closer Grant Balfour.
The 30-year-old right-hander has led the American League in saves the last two seasons, with 51 in 2012 and 50 last season, becoming the first player in major league history with back-to-back 50-save campaigns.
Mariano Rivera is the only other pitcher, in fact, to have two 50-save seasons in his career.
Last season, Johnson was 3-8 with a 2.94 ERA and 1.28 WHIP with 56 strikeouts in 70.1 innings over 74 appearances. Those numbers were all worse than his breakthrough 2012 campaign, when he posted a 2.49 ERA and 1.019 WHIP in 68.2 innings, with 41 strikeouts in 71 appearances.
The Orioles were a wild-card team in 2012, but missed the postseason last year.
While Johnson led the AL in saves in 2013, he also led the league with nine blown saves.
Johnson has been with the Orioles organization his entire career, beginning as a fifth-round draft pick in 2001 out of Union-Endicott High School in Endicott, N.Y. He made his big league debut as a starter in 2006, his lone big-league start.
In parts of eight seasons, Johnson has 122 saves and a 3.11 ERA with a 1.233 ERA in 400 innings. He has been the Orioles regular closer each of the last two seasons after filling a variety of bullpen roles from 2008-11.
Johnson relies primarily on a hard sinker, throwing it about 75 percent of the time, which occasionally mixing in a curveball and changeup, per FanGraphs.com.
Weeks, the younger brother of Milwaukee Brewers second baseman Rickie Weeks, was once a highly touted prospect in the A’s organization, a former 12th overall draft pick in 2008 out of the University of Miami.
Weeks, who will be 27 next month, debuted with Oakland in 2011, hitting .303/.340/.421 in 97 games and 437 plate appearances with 26 doubles, eight triples, two homers, 36 RBI, 50 runs and 22 stolen bases.
But he regressed in 2012, hitting .221/.305/.304 in 118 games and 511 plate appearances, with 15 doubles, eight triples, two homers, 20 RBI, 54 runs and 15 stolen bases.
He spent most of 2013 at Triple-A Sacramento, where he hit .271/.376/.369 in 130 games and 614 plate appearances, with 19 doubles, 10 triples, four homers, 40 RBI, 96 runs and 17 stolen bases.
In eight games with the A’s, Weeks was 1-for-9 with five strikeouts and scored three runs.
Statistical information from baseball-reference.com.