SAN FRANCISCO -- The Giants’ pitching depth took another blow on Sunday, when veteran Anthony DeSclafani landed on the 15-day injured list with a right elbow flexor strain prior to the club’s 4-3 walk-off win over the Red Sox in 11 innings at Oracle Park. 

An MRI exam revealed a Grade 1 strain for DeSclafani, who will be shut down from throwing for “several weeks” before being reevaluated, according to manager Gabe Kapler.

It's the second IL stint of the year for DeSclafani, who also missed 12 games with right shoulder fatigue earlier this month. The 33-year-old veteran has a 4.88 ERA over 19 appearances this season, though he’d struggled to a 6.57 ERA since May 8 and came in behind an opener in his last outing against the Nationals on July 23. 

To replace DeSclafani on the 26-man roster, the Giants recalled rookie Tristan Beck, who earned the win on Sunday after working two scoreless innings to strand two automatic runners in extra innings and give his club a chance to finally break through on Joc Pederson’s bases-loaded single off Mauricio Llovera in the bottom of the 11th.

San Francisco went only 6-for-36 (.167) with runners in scoring position during this weekend series, but it still took two of three from Boston to improve to 58-48 and pull within two games of the first-place Dodgers in the National League West.

With Tuesday’s 3 p.m. PT Trade Deadline looming, the Giants are expected to be on the hunt for reinforcements for both their lineup and their rotation, which is essentially down to two regular starters due to injuries and underperformance.

Logan Webb and Alex Cobb are the only members of the pitching staff who have been used exclusively out of the rotation this year, but the Giants have managed to piece it together with several arms who have alternated between starting and relieving, including Beck, Alex Wood, Sean Manaea, Jakob Junis and Ross Stripling.  

Stripling delivered quality starts in each of his previous two turns through the rotation, but the Giants opted to start an opener -- left-hander Scott Alexander -- against Boston for the second consecutive day. Alexander retired all five batters he faced before giving way to Stripling, who allowed only a solo home run to Adam Duvall over 4 1/3 innings in his sixth relief appearance of the year.

“You’ve got to buy in,” Stripling said. “Right now we’ve got two starters. It’s kind of all hands on deck for everyone at any time.” 

While the Giants are now 14-4 in bullpen games this year, president of baseball operations Farhan Zaidi has expressed a desire to gain more “definition and clarity” in the rotation leading up to the Trade Deadline.

“We would love to have a group of five guys that just get the ball every fifth day,” Zaidi said earlier this month. “Even though we’ve had success in the bullpen games and we’ve got guys that are willing to buy in, I think it’s just the most comfortable thing for everybody.”

Still, recent activity suggests the cost of acquiring a frontline starter will be high, which could impede the Giants’ efforts to beef up their rotation. Max Scherzer, Jordan Montgomery, Lucas Giolito and Lance Lynn have already come off the board, leaving the Mets’ Justin Verlander, the Cardinals’ Jack Flaherty and the Tigers’ Eduardo Rodriguez and Michael Lorenzen as some of the best remaining options on the trade market.

Given the demand for pitching across the Majors, the Giants could ultimately prefer to ride their current stable of arms and look for an internal boost from their farm system, though DeSclafani’s setback comes on the heels of injuries to a few top pitching prospects.

Keaton Winn was scratched from his scheduled start with Triple-A Sacramento on Friday, but an MRI exam revealed no structural damage in his sore right elbow, spurring optimism that he’ll still be able to contribute to the rotation mix this year. Kyle Harrison has been out since July 4 with a “moderate” right hamstring strain, while fellow left-hander Carson Whisenhunt seems likely to miss the remainder of his first professional season after being diagnosed with a left elbow sprain on Saturday.

Still, the Giants are confident they’ll be able to count on other young pitchers like Beck to cover meaningful innings down the stretch. Beck came up primarily as a starter, but he’s been used out of the bullpen in the Majors and said it’s been easier to adapt to the new role thanks to the example set by veterans like Stripling and Manaea. 

“When you see guys like Ross and Sean doing that and filling that kind of role, it almost gives you a little bit of a blueprint,” Beck said. “We’ve got these experienced veterans doing their thing and they’re out there having a lot of success. It definitely drives us a little bit. I kind of know where I’m at in the rotation. I’m happy to eat innings and just stay available when the team needs me.”