Something was brewing this weekend when Keaton Winn, one of the Giants’ promising young arms, didn’t make his scheduled start at Triple-A Sacramento. The 25-year-old right-hander wasn’t, to the surprise of some, at Oracle Park over the weekend, though.

Winn, a hard-throwing righty with a nasty split-finger, was called up to make his major-league debut, arriving to provide some relief to a bullpen that has covered all 18 innings of the past two games. Right-hander Tristan Beck, who has earned plaudits from Gabe Kapler for his solid work in a bulk role, was optioned to Sacramento in a corresponding move.

The move was made Monday, before San Francisco won the series opener 4-3 in St. Louis. Winn did not pitch.

Winn, 25, was rated the Giants’ No. 14 prospect by MLB.com and Baseball America in their preseason rankings. Returning from a two-year absence due to the pandemic and elbow surgery, Winn rose from Single-A San Jose to Double-A Richmond last season and began this season at Triple-A, where he has a 4.35 ERA in 12 games (nine starts) with 51 strikeouts and 21 walks in 41 1/3 innings.

He positioned himself for a promotion over his past three outings, allowing one earned run on seven hits over 12 innings (a 0.75 ERA), with 18 strikeouts and only five walks. While he doesn’t come with the pedigree of Triple-A teammate and top left-handed pitching prospect Kyle Harrison, Winn already had a spot on the 40-man roster and club personnel are excited about his future.

Hailing from cornfields of Ollie, Iowa, the Giants called up Winn to make his debut just across state lines. They plucked him out of Iowa Western JC in the fifth round of the 2018 draft and waited as he missed two full seasons, when the pandemic shut down minor league baseball in 2020 and he underwent Tommy John surgery in 2021.

When he returned, Winn had added gas on his fastball — it now touches triple digits — and quickly rose through the Giants’ system. He averaged less than a strikeout per inning pre-operation but since returning in 2022 has transformed himself into a strikeout pitcher, using his lethal combination of high-octane heater and a wipeout splitter that is considered one of the best pitches in the organization.

Winn made his first start back from Tommy John at Single-A San Jose last April. It was just over a year ago, June 5 of last season, that Winn went five innings for the first time post-surgery. Two starts later, he was promoted to High-A Eugene, where it took him eight starts to earn another promotion, to Double-A Richmond. He started 2023 at Triple-A Sacramento and, now, after 12 games, including a stretch of especially strong work his past three outings, Winn is set to become the seventh Giants rookie to debut this season.

Winn joins a group of rookies that already includes Blake Sabol, Brett Wisely, Tristan Beck, Casey Schmitt, Patrick Bailey and Ryan Walker, which should continue to grow, with Harrison and outfielder Luis Matos also making strong cases for promotions at Triple-A.

Matos, 21, the youngest player in the Pacific Coast League, has homered five times in his past five games, including two on Sunday, to raise his batting line through his first 23 games at the level to an eye-popping .396/.434/.660.

Harrison pitched into the fifth inning for the first time this season in his last start, a deliberate move to preserve his arm for the second half of the season, when he could be helping the big-league club. He struck out six and walked only one over 4 1/3 innings, another promising sign that he is more consistently finding the strike zone. Over his past four outings, Harrison has a 1.15 ERA and 25 strikeouts to eight walks in 15 2/3 innings.

Which Giants are in All-Star voting mix? >> Three Giants players ranked in the top 10 at their positions in the first All-Star Game voting update provided by MLB on Monday. However, none had a clear path to earning a starting nod without additional support.

J.D. Davis has been the Giants’ top vote-getter, with 227,536, which ranks fourth among National League third basemen. Second baseman Thairo Estrada (103,446) ranks sixth at his position, and LaMonte Wade Jr. (53,648) checks in eighth among first basemen.

Brandon Belt, now with the Toronto Blue Jays, is currently in line to advance to the second phase of voting as the second-leading vote-getter among American League designated hitters but faces an uphill battle: His competition is Shohei Ohtani.

The first phase of voting runs through 9 a.m. PT next Thursday, June 22, and the two players who receive the most votes at each position advance to a runoff to determine the All-Star starters, which will be unveiled June 29 on ESPN. The next vote update will come next Tuesday, and the entire rosters will be announced July 2 (pitchers and reserves are determined by player voting and the commissioner’s office).

At third base, Davis trails the leading vote-getter by nearly 200,000 and second place by about 150,000, behind the Cardinals’ Nolan Arenado (410,122), Atlanta’s Austin Riley (368,044) and the Dodgers’ Max Muncy (358,235).

At second, Estrada is in a hole of about 400,000 votes behind the leader, Miami’s Luis Arraez (509,092), whose batting average is still hovering around .400. To advance to the second phase, Estrada will have to overtake Atlanta’s Ozzie Albies (376,726), the Cardinals’ Nolan Gorman (245,524), the Dodgers’ Miguel Vargas (142,182) and the Mets’ Jeff McNeil (126,924), while holding off the D-backs’ Ketel Marte (102,953), fewer than a thousand votes behind.

Wade faces the biggest challenge at first base, trailing the Dodgers’ Freddie Freeman (775,503) and six others: the Mets’ Pete Alonso (377,749), Atlanta’s Matt Olson (272,275), the Cardinals’ Paul Goldschmidt (178,238), the Cubs’ Trey Mancini (79,229), the Brewers’ Rowdy Tellez (65,316) and the Padres’ Jake Cronenworth (58,289).