Those who signed after age 18 and have been in the Minors for four years, or those who signed at 18 or younger and have been in the Minors for five years, are eligible to be taken in the Rule 5 Draft. Clubs pay $50,000 to select a player in the Draft. If that player doesn't remain on the 25-man roster for the full season, he must be offered back to his former team for $25,000. Among notable players in the A's organization left unprotected are third baseman Stephen Parker and right-hander James Simmons.
The 25-year-old Green, the A's top Draft pick in 2009, could finally be in position to grab hold of an Opening Day roster spot, either as a shortstop -- his natural position -- or as a utility player, given his versatility in the infield and outfield.
Green hit .296 with 15 home runs and 75 RBIs at Triple-A this year and followed up that performance with a .273 average in 17 games for Phoenix in the Arizona Fall League, collecting two homers, 11 RBIs and 10 walks along the way. In four Minor League seasons, Green has compiled a career .296 average.
Ynoa, though only in Class A, is one of the highest regarded prospects in the A's organization, having signed with them out of the Dominican Republic in 2008 via a then-record $4.25 million bonus at age 16 -- an investment the A's likely couldn't afford to lose, despite his slow progress.
Since signing, the 6-foot-7 Ynoa, now 21, has missed significant time because of elbow injuries, which led to Tommy John surgery. He missed all of 2011, but returned in 2012 to tally 30 2/3 innings, posting a 6.46 ERA.
Leon, meanwhile, combined for a 4-1 record and 2.70 ERA in 44 relief appearances with Class A Stockton, Double-A Midland and Sacramento, fanning 74 in 66 2/3 innings. The 24-year-old righty, who has also undergone Tommy John surgery, is currently pitching for his hometown Culiacan in the Mexican Winter League and is 1-0 with a 0.79 ERA in 12 relief appearances.
Peterson was limited to 86 games this year because of an early-season ankle injury, but he managed to hit .326 with a .480 on-base percentage and .510 slugging mark when healthy. Originally a second-round pick of the Cardinals in 2008, the 24-year-old Peterson was traded to the A's with Clayton Mortensen and Brett Wallace for Matt Holliday in July 2009.
With 39 players on their roster at the beginning of the day, the A's had a difficult decision to make in designating Miller, who enjoyed four impressive stints with Oakland in 2012, gathering a 2.59 ERA and .217 opponents' average against in 33 appearances.
Then there's Hicks, who was clutch in a handful of key moments for the A's, but struggled to produce consistently. Overall, he hit .172 with three home runs and seven RBIs in 22 games spanning two stints with the A's, after being claimed off waivers by the Braves in March.