"My velocity started dipping last year and continued into the spring and the first two starts this year," the southpaw said after holding Oklahoma City to just three hits over seven shutout innings as Fresno won the back end of Monday's doubleheader, 1-0. "My arm felt good, so I knew it wasn't an injury.
"It was a slight change in mechanics that changed everything," he added. "I was turning my upper body too much before. It's hard to even see on film, but as soon as I made the adjustment, my confidence came back and I've been getting outs and hitting the inside corner. The change in mechanics really helped everything."
The other alteration was an addition to his repertoire.
"I've started throwing a cutter and that's been working really well," Bumgarner said. "I've been messing around with it in the outfield and I've only thrown it over the last two games, but it actually has been one of the better pitches."
Bumgarner (3-1) utilized his new weapon while fanning eight RedHawks and yielding just two walks on the night. He has allowed one earned run over his last two outings to lower his ERA to 3.64.
The 10th overall pick in the 2007 Draft walked Craig Gentry and yielded a single to Chris Davis in the first inning. Gentry made it to third as Davis was caught stealing second base, and Bumgarner got Chad Tracy to line out to end the frame.
Bumgarner retired the next four batters he faced until Emerson Frostad singled in the third. After Gentry walked for the second time, Bumgarner induced a double-play ball from Esteban German to end the frame.
Oklahoma City's last baserunner of the game came in the fourth when Brandon Boggs singled up the middle. Bumgarner retired the final 10 batters he faced in the seven-inning game.
"I wasn't sure what my pitch count was," he said. "They've limited me, which is a good thing. No reason to overexert yourself. I just keep going until they tell me I'm done."
For Bumgarner, the shutout marks his sixth straight outing of relinquishing no more than two runs. He had yielded 11 runs, including two homers, in his first two starts of the season before correcting his delivery.
"The last two starts, every pitch has been very good," he said. "The curveball is working the best out of all my off-speed pitches."
Last September, Bumgarner was promoted to San Francisco, where he had a 1.80 ERA in four no-decision appearances (including one start), struck out eight hitters and held opponents to a .229 average.
He may not have to wait long for another callup.
"I'm not really even thinking about it," Bumgarner said. "If you think about that stuff, you won't be able to pitch as good. I'd be happy to do it tomorrow, September or next year. But for right now, I'm keeping my mind where I'm at."