This story was excerpted from Maria Guardado’s Giants Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

SAN FRANCISCO -- Rookie left-hander Kyle Harrison made a quick rise through the Giants’ farm system by overpowering hitters with his fastball. That game plan hasn’t changed much now that he’s in the Majors.

Harrison, 22, entered Saturday having thrown his four-seam fastball 67.4% of the time this season, the second-highest rate among Major League starters who have thrown at least 250 pitches in 2024. Only Dodgers lefty James Paxton (68%) has relied more on his heater than Harrison, who has gotten positive results with the offering so far.

Opposing hitters are batting only .190 (11-for-58) with 15 strikeouts against Harrison’s four-seam fastball, which is currently tied for the third-highest Run Value (6) in the Majors.

“He’s getting results right now,” manager Bob Melvin said. “His fastball is kind of tough. You see 92, 93 [mph], but that’s not what it feels like at the plate. The fastball has been his pitch. He’s had success with it. I think he does feel more comfortable now with his breaking ball and his changeup. I think adjustments will be made along the way depending on what kind of swings you’re getting off the fastball. But so far, so good.”

While Harrison’s fastball has been dominant, his secondary offerings have been far more hittable, with opposing batters going a combined 14-for-31 (.452) with four strikeouts against his changeup, slurve and slider.

Harrison has managed to remain effective and deliver quality starts in three of his first four outings this year, though he'll likely need to develop another weapon that can help keep hitters off his fastball in the future.

Harrison threw his slurve 26.5% of the time in 2023, but he almost completely abandoned the pitch in his last start against the Marlins on Monday. Only four of his 85 pitches (5%) were slurves, one of which was crushed out to left-center field by Avisaíl García for a solo home run.

“That’s not ideal for me,” said Harrison, who has a 2-1 record with a 4.70 ERA through his first four starts of the year. “I want to figure out that slider again. It’ll be back. It’s coming back. Next bullpen session. I feel like it’s almost there. It’s a weird thing too because that’s a pitch that I haven’t really lost. I’ll get there. I wouldn’t say I lost it, but it’s just throwing it with the right conviction.”

While he’s still working to get his breaking ball back on track, Harrison has been pleased with the progress he’s made with his changeup, which he’s now throwing 22.9% of the time this year, up from 11.1% in 2023.

“I’m kind of discovering how well I can throw that and how much of a weapon it is,” Harrison said. “It’s something I really didn’t utilize last year and even in Spring Training. I think it’s something that’s coming along. It’s something that I can get outs with and kind of set guys up for.”