Banuelos, 23, is a former top pitching prospect. He missed nearly all of 2012 and '13 because of Tommy John surgery and subsequent rehab setbacks. The left-hander went 2-3 with a 4.11 ERA in 26 combined appearances (25 starts) at three levels of the minors this past season, and in his final 15 innings for Triple-A Scranton/Wilkes-Barre, he had a 3.60 ERA, striking out 13 and walking 10.
Carpenter, 29, a right-handed reliever, went 6-4 with three saves, a 3.54 ERA and a 1.26 WHIP in 65 games for the Braves this past season. He made his major league debut with Houston in 2011 and is 11-10 with a 3.62 ERA in 188 career games.
Shreve, 24, a left-handed reliever, made his major league debut in July and allowed one earned run in 12 1/3 innings covering 15 games. He posted a 0.73 ERA and 1.05 WHIP with 15 strikeouts.
Information from ESPN.com's Keith Law and Andrew Marchand and The Associated Press contributed to this report.