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.