Less than five weeks into the regular season, the Giants have lost their two primary second basemen.

As expected, Tommy La Stella landed on the injured list with a left hamstring strain on Tuesday, joining fellow veteran infielder Donovan Solano, who has been sidelined since April 22 with a right calf strain.

Manager Gabe Kapler said La Stella is expected to miss four to six weeks, a significant loss considering the 32-year-old had settled in as the Giants’ leadoff man against right-handed pitching. Solano is running sprints, playing catch and hitting in the cage, but the Giants still don’t have an exact timetable for his return.

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La Stella, who joined the Giants on a three-year, $18.75 million deal during the offseason, batted .235 with a .297 on-base percentage through his first 25 games, but he went 2-for-3 with two RBIs before tweaking his hamstring while scoring from third base against the Padres on Sunday.

“Obviously, there’s frustration, but I know that injuries are part of the game,” La Stella said. “Now I’m best served to put my attention on getting back as quickly as possible and making sure that this isn’t an issue going forward.”

To replace La Stella, the Giants recalled infielder Jason Vosler from their alternate training site ahead of a doubleheader Tuesday against the Rockies at Coors Field. San Francisco also appointed left-hander Conner Menez as its 27th man for both games of the doubleheader.

Vosler, 27, is another versatile left-handed-hitting infielder who can play third, second and first base as well as the corner outfield spots. He made his big league debut last month and is 2-for-8 with a double and a stolen base in four games with the Giants.

Vosler is likely to fill a role similar to La Stella’s, drawing starts at second base against right-handed pitching and helping to back up Evan Longoria at third base. He started at third base in the first game against the Rockies on Tuesday, with Wilmer Flores getting the nod at second. Mauricio Dubón will also be a candidate to fill in around the infield while La Stella and Solano are on the mend. 

“This team is incredibly deep, and anybody who is going to be filling in and anybody who is going to be on the field is more than qualified,” La Stella said. “I think one of the unique aspects of this team is our depth.”

Gausman to IL; Bart recalled
Less than an hour before the first game Tuesday, the Giants placed right-hander Kevin Gausman on the IL with side effects from the COVID-19 vaccine and recalled catcher Joey Bart from the alternate training site. Gausman, who pitched six innings of one-run ball against the Padres on Sunday, is being monitored by the Giants’ training staff and is expected to be back to normal in the next couple of days.

The Giants made a similar move with Logan Webb and Jake McGee last month after the two pitchers experienced lingering side effects from their second doses of the COVID-19 vaccine. Webb and McGee missed only two games before returning to the Giants, as there is no minimum stay for the COVID-19 IL.

Bart, 24, will give the Giants a third catcher behind Buster Posey and Curt Casali. Bart, ranked by MLB Pipeline as the club’s No. 2 prospect, batted .233 with a .609 OPS over 33 games with the Giants in 2020.

Dickerson exits
The Giants removed left fielder Alex Dickerson from the first game of their doubleheader Tuesday with right shoulder soreness. Dickerson jammed his shoulder while making a diving catch against the Padres on Sunday.

“He was having a little bit of trouble with that front shoulder after diving for that ball in San Diego,” Kapler said.

Mike Tauchman shifted from right field to left in the second game to replace Dickerson, who went 1-for-3 with an RBI hit in the opener.