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8/27/2014 10:25 P.M. ET

Shoemaker's splitter giving hitters splitting headache

ANAHEIM -- Fourteen-year-old Matt Shoemaker was struggling to find the right changeup.

Shoemaker and his father had toyed around with different grips and ultimately landed on the one that has carried him through his first full season in the Majors -- his splitter.

Shoemaker's disappearing splitter has baffled hitters so far this season and helped him go 13-4 with a 3.33 ERA. The 27-year-old right-hander picked up his 13th win of the season Tuesday night by tossing seven shutout innings against Miami, extending his scoreless streak to 16 2/3 innings.

The splitter has accounted for 62 of his 108 strikeouts (57 percent), according to Brooks Baseball, despite being used only 20 percent of the time.

"I'll use it where a guy would use a changeup and I'll throw that for a strikeout," Shoemaker said.

Hitters have been aggressive against the offspeed offering (swinging 63 percent of the time, by far the highest among Shoemaker's pitches) but have whiffed often (37 percent of swings, also the highest). Shoemaker has turned those misses into strikeouts, in part because he throws it about half the time he has two strikes.

When hitters have managed to make contact, it hasn't been solid. Balls in play are on the ground half the time (52 percent) against the splitter, while hitters have a .156 average against the pitch. The next lowest batting average for a Shoemaker pitch is .247 on his slider.

In his one-hit effort against Boston last Thursday, Shoemaker threw a season-high 30 splitters, helping to coax nine groundouts and nine strikeouts.

Angels have few options left for Saturday's start

ANAHEIM -- The Angels' search for a potential fifth starter took a hit on Tuesday night, when Chris Volstad was scratched from a start in Triple-A with a sore elbow.

Volstad, one of the few options the Angels have for Saturday's start against the A's, is not expected to be ready to start this weekend, seemingly narrowing the options to Double-A starters Michael Roth and Drew Rucinski and Triple-A left-hander Randy Wolf. The Halos need a starter with ace Garrett Richards out for the season.

Angels manager Mike Scioscia even mentioned current reliever Cory Rasmus as a possible option. Rasmus threw a career-high 51 pitches on Monday, but he has never started a Major League game.

"We've got some guys that are currently on our 25-man roster that we could look to get that game done, and there are some guys in the organization we could look at," Scioscia said.

Roth appears the most likely to start, having thrown seven shutout innings on Monday, which would put him on normal rest for Saturday. In 22 starts at Double-A Arkansas, Roth is 11-7 with a 2.62 ERA. He has also appeared in two games for the Angels, allowing four runs in 6 2/3 innings.

Rucinski, meanwhile, started Sunday's game for Arkansas, giving up four runs in five innings while recording 11 strikeouts. Like Roth, Rucinski has pitched for the Angels (two runs in one inning in July) and remains on the 40-man roster.

Wolf is not currently on the 40-man roster (meaning the Angels would need to make room for him by potentially losing a player) and last pitched Sunday for Salt Lake. The 38-year-old veteran surrendered four runs on eight hits across seven innings.

"You don't have a crystal ball, but you always try to project performance and project what both pitchers can do and make the best choice you can on who you think is going to perform better," Scioscia said.

Saturday's start will be the last one by the No. 5 starter before rosters expand on Monday and allow the Angels more pitching depth and flexibility to get through the remaining games.

"You're always going to have that challenge of depth in a starting rotation, and I think you have to find ways to hold your own and win some of those games, when maybe it's not your [No. 1] or 2 or 3 pitcher, and that's what we'll have to do," Scioscia said.

Hamilton honored with Lou Gehrig Award

ANAHEIM -- Angels outfielder Josh Hamilton was named the Lou Gehrig Memorial Award winner on Wednesday, becoming the first Angels player to win the honor.

The award, given annually by the Phi Delta Theta fraternity, "was created to acknowledge an individual player's outstanding commitment to both his community and philanthropy," according to the organization's website.

The Gehrig Award plaque remains in Cooperstown and has every winner's name etched into it. Albert Pujols won the award in 2009 with St. Louis.

Hamilton will be honored with a ceremony before Thursday's game against Oakland.

Worth noting

• Albert Pujols left Wednesday's 6-1 win over the Marlins in the seventh inning after fouling a ball off his calf, which "was a little tight," according to Scioscia. The manager said he expects Pujols in Thursday's lineup.

• For the second time in four games, Howie Kendrick started as the designated hitter on Wednesday. Gordon Beckham started in his place at second base.

Scioscia said Kendrick's health was fine. It was simply a "refresh day."

• The Arkansas Travelers, the Angels' Double-A affiliate, clinched the Texas League's north division championship and a playoff berth with a 5-4 win over Springfield on Wednesday.

Rookie affiliate Orem clinched a playoff spot in July by winning the Pioneer League's first-half south division championship.

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.