SAN FRANCISCO -- In a convenient sequence of transactions Sunday, the Giants trimmed payroll by trading two expendable veterans, whose departures create playing opportunities for a pair of prospects.

San Francisco swapped outfielder Austin Jackson and right-hander Cory Gearrin , along with Minor League right-hander Jason Bahr, to the Texas Rangers for a player to be named or cash considerations.

That freed the Giants to raid the cupboard at Triple-A Sacramento by purchasing the contracts of outfielder Steven Duggar, widely considered the organization's leadoff batter and center fielder of the future, and right-hander Ray Black , the triple-digit-fastball-throwing reliever who's finally healthy.

"For us, it cleared up a couple spots there for these two kids," Giants manager Bruce Bochy said. "In fairness, Austin's playing time was cut back. He wasn't getting a lot of starts recently. I can't say enough about him and Cory, what great teammates they were. Even times they weren't getting the playing time that they were probably hoping, they were great. They were pulling for the guys. They were awesome in the clubhouse. Two class guys that we're going to miss."

But, Bochy added, "We were hoping to find a way to get Duggar up here along with Black."

By jettisoning Jackson, who signed a two-year, $6 million deal as a free agent last offseason, and Gearrin, who has a $1.675 million salary, the Giants gave themselves a better chance to operate under the $197 million threshold of the Competitive Balance Tax. Each team's figure won't be determined until the end of the season.

By comparison, Duggar and Black will be paid the pro-rated portion of the $545,000 minimum salary.

"What this does is it does create some additional buffer and flexibility below [the CBT] that we can use as a way to improve the club if the opportunity comes at the [non-waiver Trade] Deadline or along the way," Giants general manager Bobby Evans said.

Bochy wasted no time in giving Duggar a chance to prove himself, installing the 24-year-old in center field and atop the batting order Sunday. Bochy indicated the left-handed-batting Duggar and the right-handed-swinging Gorkys Hernandez , whose emergence limited Jackson's playing time, will platoon at times but not daily. Bochy added that Hernandez will remain a regular, occupying left field when Duggar's in center.

Sacramento manager Dave Brundage interrupted Duggar's dinner Saturday to give him the big news.

As Duggar related, Brundage said, "'You can go to the Triple-A All-Star Game or you can go to the big leagues.' It was exciting, to say the least."

Duggar, rated the organization's No. 3 prospect by MLB Pipeline, was batting .272 with 27 doubles, four triples, four homers and 21 RBIs in 78 games at Sacramento.

Black, the Giants' 29th-rated prospect according to MLB Pipeline, was 2-0 with a 2.27 ERA in 22 games with Sacramento and 10 with Double-A Richmond. He had 58 strikeouts in 31 2/3 innings at the two classifications, bringing his career Minor League totals to 240 strikeouts in 125 2/3 innings.

Drafted in the seventh round out of the University of Pittsburgh in 2011, Black has endured multiple injuries and mishaps since high school, beginning with Tommy John elbow surgery in 2009, knee and hand surgeries, labrum surgery and the removal of a bone spur from his elbow. Before this season began, he seriously considered retiring from baseball to work at the family farm in Hanover, Pa.

"It's been a crazy road," said Black, 28. "There have been a lot of ups and downs. Roller coaster of emotions. A few months ago I didn't know if I was going to be playing any more to get to this point right now. It's incredible. I'm just grateful for the opportunity to be here."

Jackson, who batted .242 with 13 RBIs in 59 games, received significantly less playing time as Hernandez established himself as a reliable performer. More recently, outfielder Austin Slater 's arrival from Sacramento limited Jackson's activity primarily to pinch-hitting. Jackson started one game since June 16.

Gearrin, 1-1 with a 4.20 ERA in 35 games, was an integral part of the bullpen but was used less frequently in high-leverage situations that were entrusted more often to the likes of Sam Dyson, Reyes Moronta , Tony Watson and Will Smith.

Evans noted that Bahr, 23, was not just a throw-in. He owned an 8-4 record and a 2.55 ERA in 16 starts at San Francisco's pair of Class A affiliates, San Jose and Augusta.

Chris Haft has covered the Giants since 2005, and for MLB.com since 2007. Follow him on Twitter at @sfgiantsbeat and listen to his podcast.