ANAHEIM -- Ernesto Frieri has this fastball he throws that nobody can seem to figure out. One scout calls it "the invisible fastball." Angels general manager Jerry Dipoto simply refers to it as "one of those magic fastballs." Frieri just calls it "sneaky."

Whatever it is, it's resulting in a whole lot of strikeouts, a whole lot of zeros and a whole lot of stability to the back end of an Angels bullpen that looked lost before Frieri came from San Diego on May 3.

Frieri threw 13 hitless innings to begin his Angels career (making him the first pitcher in Major League history to not allow a hit in his first 13 appearances with a team, according to the Elias Sports Bureau) and struck out 27 batters in the process (the first to do that and not allow a run since at least 1921, according to STATS LLC).

Frieri will occasionally toy with a slider, but he really only throws one pitch -- that whatchamacallit fastball -- and it hardly clocks higher than 94 mph.

"It's actually really easy to catch," Angels backup catcher John Hester said. "He just attacks the strike zone and hitters just miss it. ... He's amazing everybody. We don't know exactly what he does or how he does it, but it's working."

So, why can't anybody seem to make contact off him?

First off, Frieri's delivery is awfully deceptive. He steps across his body, similar to Jered Weaver, and tucks the ball behind his right side while striding toward the plate, making it invisible to the hitter until it comes out of his hand.

"You don't see it until the very last minute," said Rangers slugger Nelson Cruz, one of two strikeout victims for Frieri in Friday's ninth inning. "He hides it really well."

Second is the movement it creates. With flexible fingers -- like Pedro Martinez -- and a whip-like motion with his right wrist, Frieri can create that movement. If he tilts his wrist a little bit to the right or left upon delivery, the ball will go accordingly. If he keeps it locked -- as he tends to do when behind in counts -- it'll stay straight.

At any given time, though, there's no telling where it will go.

"It's a blessing God gave me," Frieri said. "No doubt about it."

The third factor, perhaps, is how mysterious he still is to the hitters he's facing. Frieri, 26, spent his entire career pitching for the Padres organization and had pitched only 8 1/3 innings against American League competition heading into this season.

Safe to say very few of them have ever seen a fastball like his.

"I think I've been blessed, and probably had a little luck that things have gone that way," said Frieri, who has also walked 10 but converted all three of his save chances. "These guys are great hitters. Maybe they've never seen a pitcher with the kind of stuff I have. But I know, in time, they'll get to know me better and things will be a little difficult. But up until now, I'll keep doing the same things."

The Rangers' Mike Napoli singled off Frieri with one out in the ninth of Saturday's 3-2 Angels win to snap his streak.

Hawkins to begin rehab assignment on Sunday

ANAHEIM -- Reliever LaTroy Hawkins, who has been out since May 6 with a broken right pinkie finger, will begin a rehab appearance with Class A Inland Empire on Sunday, with the hope of returning to the Angels' bullpen two outings later.

"Most likely he'll need at least two," manager Mike Scioscia said. "He'll go tomorrow, then we'll see how he comes out of it."

Hawkins, with a 1.08 ERA and 1.32 WHIP in 8 1/3 innings this year, injured the pinkie while fielding a comebacker that resulted in a game-ending double play against the Blue Jays a little less than four weeks ago. The 39-year-old, now without a splint, threw a 20-pitch simulated game on Friday and came out of it fine.

Jered Weaver, nursing a lower back injury, played light catch on Saturday.

Conger back in action, now an option

ANAHEIM -- Angels catching prospect Hank Conger returned to action at Triple-A Salt Lake on Thursday, after missing more than a month with an injured throwing elbow, and delivered a walk-off single on Friday night.

But that's not the biggest development. It's that Conger, if healthy and back to his normal self, could be an option for the Angels as they wait for starter Chris Iannetta to recover from wrist surgery.

Conger, who had been serving as a designated hitter in extended Spring Training recently, caught his first game Thursday, DH'd on Friday and was expected to be behind the plate again on Saturday.

"Hank's a guy that when he plays to his potential, he's going to be a terrific player," Angels manager Mike Scioscia said. "He was working through some things on the defensive end this spring. Now, he feels much better with them, and we'll see how Hank progresses."

With Iannetta out, Bobby Wilson (.181 batting average) has done the majority of the catching and John Hester (.294) has been the backup. Questions have always surrounded Conger's ability defensively -- and he's particularly been working through his throwing -- but few have ever questioned the switch-hitter's ability to hit.

With the Angels, either as a new backup, or perhaps a third catcher, Conger could help a position that currently ranks 26th in the Majors in collective OPS.

Conger, 24, hurt his right elbow while throwing to second base on a 3-2 pitch during the second series of the Triple-A season. The umpire called a ball on an attempted steal, and instead of throwing through, Conger pulled back and "heard a loud crackle" in his elbow, which eventually forced him out of game action past April 21 and cost him an opportunity to be called up when Iannetta underwent wrist surgery on May 11.

"I definitely want to try to get up there to try to help the team, but at the same time, I have to make sure I'm 100 percent," Conger, who played in 59 games for the Angels last year, said in a recent phone conversation. "Especially with the elbow, that's a very sensitive thing where you have to really make sure you're 100 percent and not letting it linger toward the rest of the season."

Iannetta has been throwing lightly with a splint on his right wrist and isn't expected back until late June or early July.