The A's made a series of moves on Tuesday, acquiring right-hander Tanner Anderson from the Pirates and adding outfielders Skye Bolt and Luis Barrera and right-handers Grant Holmes and James Kaprielian to their 40-man roster, effectively shielding them from the Rule 5 Draft.
Oakland will send either a player to be named later or cash to Pittsburgh.
Anderson made his Major League debut with the Pirates in 2018, compiling a 6.35 ERA in 11 1 1/3 innings. The 25-year-old Harvard product struck out 221 in 311 1/3 Minor League innings, pitching to a solid 3.24 ERA over four seasons.
Anderson joins several new additions to Oakland's 40-man roster, which sits at 39 ahead of the Dec. 13 Rule 5 Draft, during which teams select players from other organizations who aren't on their club's 40-man roster.
Players drafted or signed at age 18 or younger are eligible after five Minor League seasons. Those drafted or signed at an older age are eligible after four Minor League seasons. That means any player not on the 40-man roster who signed in 2014 at 18 years or younger or in '15 at 19 years or older is a candidate this year.
Among those left unprotected by the A's: 2015 first-rounder Richie Martin. A late bloomer, Martin finally found his groove this year, hitting .300 while reaching base at a .368 clip and stealing 25 bases while maintaining a strong defensive presence at shortstop.
Bolt was also a member of the A's 2015 Draft class, enjoying his most productive season in 2018. The switch-hitting outfielder combined for 19 homers and an .821 OPS between Class A Advanced Stockton and Double-A Midland. The 24-year-old also totaled 69 RBIs and stole 19 bases.
Like Bolt, Barrera finished the season with Midland, batting .328 with an .828 OPS in 36 games for the RockHounds. He was exposed to the Rule 5 Draft last year, but wasn't selected and remained in the A's organization, now giving them additional depth among a lengthy list of outfielders.
Holmes and Kaprielian are both products of trade, Holmes via the 2016 deal that sent Josh Reddick and Rich Hill to the Dodgers, and Kaprielian through last year's swap with the Yankees for Sonny Gray.
Holmes, 22, concluded his rehab from a nagging shoulder injury in time to make two appearances for Stockton this year. A first-round pick of the Dodgers in 2014, the right-hander has a 4.13 ERA in 92 Minor League outings, 83 of them starts. MLB Pipeline has him ranked as the organization's No. 15 prospect.
Kaprielian, a first-round pick of the Yankees in 2015, comes in at the A's ninth-ranked prospect. He's been out of action since 2016 after undergoing Tommy John surgery and hasn't pitched above Class A, but remains an intriguing prospect and is projected to be ready for Spring Training.