SAN FRANCISCO -- The radar readings for Jordan Hicks on Sunday seemed to be cause for concern at first glance. But the normally hard-throwing right-hander had an explanation for his diminished velocity.

A little more than an hour before first pitch, Hicks ate his pregame meal and washed it down with water. Then he threw it all up -- but by that point, he had to continue with his pre-start routine, leaving him with little time to replenish. While he didn't feel unwell on the mound, Hicks felt weaker than usual as a result.

"I don't feel sick at all," he said. "All the fuel I had in my body left."

In the first inning of the Giants' 4-1 win over the Rockies, Hicks' velocity was down across the board, most notably on his sinker. He threw 12 of them in the opening frame with an average velocity of 90.4 mph, 4.9 mph slower than his season average on the offering.

Hicks had dialed back his velocity upon converting to a starting role with the Giants, but not as much as he did on Sunday. As the afternoon went on, Hicks' velocity inched back toward the mean -- he regained some strength by snacking on bananas and Stroopwafels between innings and eventually topped out at 96 mph on his four-seamer -- but it was still well below season average on all of his pitches:

Sinker: 91.4 mph average velocity, down 3.9 mph from season average, 36 pitches

Splitter: 80.6 mph, down 4.4 mph, 20 pitches

Sweeper: 78.1 mph, down 3.6 mph, 11 pitches

Four-seamer: 92.3 mph, down 4.2 mph, five pitches

Hicks threw only five pitches at 94 mph or harder on Sunday, fewer than only his 27 such pitches on May 8 in Colorado.

"He wanted to pitch," manager Bob Melvin said. "He pitched completely different, without the velo, and found a way to give us five innings. I wasn't going to push it past five, regardless, with just kind of the lack of oomph he had behind it."

Radar readings aside, Hicks was sharp as the Giants extended their season-best winning streak to four games and swept the Rockies to cap a 6-3 homestand. Ryan McMahon took him deep for a solo shot in the first, but that was the lone run Hicks gave up across five innings. In all, he allowed three hits while striking out one and walking one on 72 pitches.

After trailing for most of Hicks' outing, the Giants backed him by taking the lead in a three-run fifth inning and added on with Heliot Ramos' solo blast in the sixth, his first of the season.

While Hicks can still bring the heat on the mound, part of his transition to starting has been learning how to pitch without his best stuff. A big piece of that puzzle is leaning on his entire arsenal.

"It makes it a little bit easier when you have four pitches to go and choose," Hicks said. "Slider, I only really had it at the top of the zone today. Splitter was doing all kinds of things, going down, breaking left -- as long as those pitches have depth. … Curt [Casali] did a really good job today calling the game. I didn't have to shake that much, just trusted him."

Sunday was Hicks' first time working with the veteran backstop, who caught his third game since rejoining the Giants last Wednesday. Melvin also pointed to Casali's presence behind the plate as a factor in Hicks being able to put up a solid outing despite not feeling his best.

"Curt seems to be able to settle in with guys pretty quickly, even guys he hasn't caught before," Melvin said. "He's got great feel. … And Jordan has been, this year, pretty good about identifying what's been working for him and how to kind of manage what he's feeling."

Casali may not have had to catch triple-digit heat from Hicks, but he remembers how daunting it was to step in against him. Now that he's become his batterymate, Casali has gotten a look at the other ways Hicks can be effective.

"He went out there and performed really well with what he had," Casali said. "It kind of goes to show that you don't need super high-octane velocity to get through a lineup. Just pick and choose your spots, throw sliders and splits, and he executed really, really well today."