SAN FRANCISCO — A day after left-hander José Álvarez started in place of Johnny Cueto, the Giants are sending Cueto to the mound against the Milwaukee Brewers.

Cueto was scratched from his scheduled start Monday as the right-hander felt ill and was placed on the COVID-19 injured list prior to the team’s series-opener against the Brewers. The veteran starter tested negative for COVID-19 twice on Monday, but manager Gabe Kapler said the team would continue to monitor his status and make an effort to “get him healthy as quickly as possible.”

Kapler said Cueto arrived at Oracle Park on Tuesday feeling much better and the Giants are optimistic he’ll be able to give the team quality innings against the Brewers. In the event Cueto is unable to pitch, the club added right-hander Kervin Castro to the taxi squad.

Castro, 22, has yet to make his major league debut, but has pitched for Triple-A Sacramento throughout the 2021 season and has been the River Cats’ most consistent arm as he’s posted a 2.93 ERA over 43.0 innings.

Aside from activating Cueto, the Giants added left-hander José Quintana to the 26-man roster Tuesday a day after claiming the veteran on waivers from the Angels. To make room for the two pitchers, the Giants optioned reliever John Brebbia and infielder Jason Vosler to Triple-A.

Quintana is expected to pitch in relief for the Giants after splitting time between the rotation and bullpen for the Angels this season. The southpaw from Colombia had a 6.74 ERA in 24 games (10 starts), but struck out a career-high 12.3 batters per nine innings.

Price & Product Availability Tracker

Discover where products are available & compare prices

Left-hander Alex Wood was originally scheduled to start Tuesday’s game against Milwaukee, but Wood became the second Giants player in the last week to test positive for COVID-19 after infielder Donovan Solano tested positive in New York on Thursday.

Solano was fully vaccinated, but Kapler has not disclosed the vaccination status for either Wood or Cueto.

Kapler said Monday that Wood was “not feeling well at all, and he’s really broken up about it.” The Giants’ manager had spoken in recent days about how eager Wood was to help the Giants during their stretch run and how motivated he was to save a bullpen that’s seen its workload increase during the second half of the season.

According to a MLB Operations Manual distributed to all 30 teams prior to the start of spring training, “individuals who test positive (for COVID-19) will be required to isolate for a minimum of 10 days, receive appropriate care and monitoring from the Club medical staff, and be cleared by the Joint Committee and the individual’s team physician, following a mandatory cardiac evaluation and a determination that the individual no longer presents a risk of infection to others.”

Longoria gets cortisone shot

After a visit with Dr. Scott Hansen on Monday, third baseman Evan Longoria received a cortisone shot and was taking the day off from hitting on Tuesday.

Longoria has been out since August 18 with a right hand contusion after taking a pitch from Mets reliever Edwin Díaz off his index finger. The Giants were initially optimistic Longoria would be activated when he was eligible to come off the injured list on Tuesday, but he’ll need at least a few more days of rest before rejoining the club.

The Giants are able to activate two additional players on Wednesday when MLB allows teams to expand rosters from 26 to 28 players and it’s possible the club could have two pitchers join the club to help a bullpen that covered all nine innings in Monday’s 3-1 loss to the Brewers.

Castro and rookie Camilo Doval are candidates to join the team, but with Wood and Solano on the COVID-19 injured list, the Giants also have one open 40-man roster spot and could select the contract of a veteran pitcher at Triple-A such as Scott Kazmir or Logan Ondrusek.