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8/26/2014 9:59 P.M. ET

Struggling Cowart among Angels prospects in AFL

ANAHEIM -- Eight Angels prospects will participate in this year's Arizona Fall League as members of the Mesa Solar Sox.

Right-handed pitchers Trevor Gott, Dan Reynolds and Mark Sappington, left-handed pitcher Nate Smith, infielders Kaleb Cowart and Eric Stamets, and outfielders Chad Hinshaw and Cal Towey will participate in the AFL. Class A Inland Empire pitching coach Matt Wise will be part of the coaching staff.

Stamets will be a "taxi-squad" member who will only be activated on Wednesdays and Sundays.

Cowart is the highest regarded Angels prospect among those on the roster, ranked No. 4 in the organization by MLB.com. He has struggled this season in Double-A Arkansas, hitting just .224/.293/.325.

Sappington (No. 9), Gott (No. 14) and Towey (No. 17) are also ranked among the Top 20 Angels prospects.

The AFL, which begins in early October and runs through mid-November, has produced 212 All-Stars, 12 Most Valuable Players and four Cy Young Award winners. Nearly 60 percent of participants have reached the Majors.

"It's a higher-caliber player that plays there, so you're going to be playing against better talent on a better team," Angels manager Mike Scioscia said. "Anytime you do that, it helps you to grow as a player, and I think the next progression is winter ball."

Halos designate LeBlanc, continue search for starter

ANAHEIM -- The experiment continues for the Angels.

One day after left-hander Wade LeBlanc lasted just 3 1/3 innings in a 7-1 loss to the Marlins, the organization designated him for assignment Tuesday, ending LeBlanc's brief stint as an Angels starter and ensuring that the club's search for a No. 5 starter continued.

LeBlanc -- whose start Monday was his first Major League one in 15 months, and his shortest in three years -- was shelled for six runs on seven hits and three walks, providing only a brief respite for a tired bullpen. He was designated for assignment by the Angels for the second time this season.

The Angels added reliever Yoslan Herrera for bullpen depth.

"I think we have confidence is what Wade can do when he's throwing the ball to his capabilities," Angels manager Mike Scioscia said. "Last night, we didn't see that.

"This isn't a reactionary move to a bad outing from last night to say that we're looking past Wade LeBlanc. Right now, in the short term, we have to because we really don't have many options for these next couple days, and you need a fresh arm out there."

LeBlanc started in place of injured right-hander Garrett Richards, who was lost for the season when he tore his patellar tendon in Boston on Wednesday. Richards was having a breakout season (13-4, 2.61 ERA), and his injury only depleted an already thin pitching staff that was without Tyler Skaggs.

With LeBlanc crossed off the list -- and Saturday's start against Oakland left vacant -- the Angels must now scramble to fill a rotation spot.

Possible options include Triple-A arms Randy Wolf (0-1, 4.99 ERA) and Chris Volstad (2-1, 6.18), or Double-A starters Michael Roth (11-7, 2.62) and Drew Rucinski (10-6, 3.22).

Roth and Rucinski are currently on the 40-man roster, meaning the Angels could recall either one without having to lose anyone from their roster. Roth is perhaps the most likely to start after throwing seven shutout innings for Arkansas on Monday night.

The Angels could also pick up a pitcher via waivers to shore up the back end of the rotation. Mets starter Bartolo Colon and Astros starter Scott Feldman both reportedly cleared waivers on Monday.

"If you're asking me, 'Does our team need pitching depth?' my answer is going to be the same even if we have a full contingent of Garrett Richards here and Tyler Skaggs," Scioscia said. "You'd say, 'Yes, you need pitching depth.' That's just the nature of this game. You always need to pay attention to your pitching depth, and I know that we are."

Herrera back to help beleaguered Halos bullpen

ANAHEIM -- The Angels added Yoslan Herrera to their bullpen on Tuesday, selecting his contract from Triple-A Salt Lake to take Wade LeBlanc's roster spot.

Herrera owns a 2.52 ERA with 8.46 strikeouts per nine innings and five saves in the Minors this season. The 33-year-old right-hander from Cuba had a 4.50 ERA in six games for the Angels in April, not allowing a run in four of them.

"Our reports from guys in Triple-A is that he's been throwing the ball better than anyone down there out of the bullpen," Angels manager Mike Scioscia said. "His velocity is up a little bit. We saw him a little bit earlier this year, but I don't think we saw a guy that is at the level that he is now. We're hoping that if we have to pitch Herrera, that he'll get out there and give us the innings we need."

The Angels have relied on their bullpen to throw 36 2/3 innings in their previous 11 games (3 1/3 per game) and have only used two relievers or fewer in a game twice during that span.

Tuesday's game was the Angels' 12th in as many days, and they won't receive a break until Monday, one day after a crucial four-game series against Oakland.

"On a short-term basis, I think we are desperate for an arm up here tonight," Scioscia said. "Wade didn't quite pitch as deep as we had hoped, and I think that our focus has to be on making sure that we're not overworking some guys in the bullpen. So we need an arm, and that was the only move we had open to us right now."

Worth noting

• Skaggs, who underwent Tommy John surgery on Aug. 13, returned to the Angels' clubhouse Tuesday for the first time since having surgery.

Skaggs, who had a 4.30 ERA in 18 starts, wore a brace on his left elbow and said the elbow felt "brand new."

The 23-year-old left-hander has been working on squeezing a ball, and he said the next step of his rehab will be to expand the range of movement of his elbow. Skaggs will miss the remainder of this season and all of next year while recovering.

• Josh Hamilton started as designated hitter for the second consecutive night on Tuesday, the second time this season he's served as DG on back-to-back nights. In 11 games as the DH, Hamilton has a .357/.471/.643 slash line and three home runs.

Matthew DeFranks is an associate reporter for MLB.com. Follow him on Twitter @MDeFranks. This story was not subject to the approval of Major League Baseball or its clubs.