Here are the Giants' options to replace Estrada

This story was excerpted from Maria Guardado’s Giants Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

SAN FRANCISCO -- The Giants absorbed their toughest injury blow of the season on Monday, when second baseman Thairo Estrada was diagnosed with a left hand fracture that is expected to sideline him for the next four to six weeks.

Estrada, who suffered the injury after being struck on the hand by a pitch from Mets reliever Adam Ottavino on Sunday, has been arguably the Giants’ most valuable player this season, leading the club with 2.6 Wins Above Replacement, according to FanGraphs. A borderline All-Star, Estrada was batting .272/.327/.434 with nine home runs and a team-high 18 stolen bases over 70 games this year.

The 27-year-old Venezuelan had slowed down at the plate in recent weeks, but he still continued to provide value through his defense, ranking first among Major League second basemen with 11 Outs Above Average this season.

With Estrada likely out until at least August, the Giants are expected to lean on two rookies -- Casey Schmitt and Brett Wisely -- to help fill their void at second. Wilmer Flores also has experience playing the position, but he’s made only two appearances there this season, because the ban on defensive shifts has made it more challenging to hide his limited range.

Schmitt and Wisely, who was recalled from Triple-A Sacramento on Monday, can offer plenty of athleticism on the dirt, but they’ll have to show more with the bat to take over the starting job at second. Schmitt batted .343 over his first 17 games with the Giants, but he’s struggled to break out of an extended slumped since then, hitting only .146 over his last 29 games. Wisely has hit .188 over 34 games while toggling between Triple-A Sacramento and the Majors this year.

“It’s going to be very much a read-each-situation-day-by-day kind of thing,” manager Gabe Kapler said. “It’d be nice to see Casey get another run at playing time. He’s going to have to earn it.”

The Giants could try platooning Schmitt and the left-handed-hitting Wisely in the interim, but they also have a couple of other options they could explore at Triple-A Sacramento. Isan Díaz went 0-for-8 after making his Giants debut last month, but he’s batting .280 with a .953 OPS and five homers over 12 games with the River Cats.

San Francisco could also take a look at Tyler Fitzgerald, who has been splitting time between the infield and center field this year. Fitzgerald isn’t on the 40-man roster, but he’s impressed by batting .296 with an .876 OPS and 11 home runs over 63 games at Triple-A Sacramento.

“Losing Thairo on a fractured hand, that’s a big loss for us,” third baseman J.D. Davis said. “At the same time, it brings a great opportunity for some rookies to come up and see some pitches, see some at-bats, see some reps and see what they got.”