Both Muñoz and Lawson sustained damage to their ulnar collateral ligaments during Spring Training, general manager A.J. Preller said. Both players underwent MRIs, then received second opinions, before opting for surgery.
Muñoz, a 21-year-old with a fastball that routinely touches 100 mph, was a strong candidate for a place in a deep Padres bullpen. He made his Major League debut last season and posted a 3.91 ERA with 30 strikeouts in 23 innings.
Muñoz made only one appearance during Spring Training, a scoreless outing against the Mariners on March 5. He felt a strain on his elbow while throwing a slider, but felt fine after the game. A couple days later, however, Muñoz developed some soreness, and a subsequent MRI showed “a compromised ligament," Preller said.
Although the Padres boast arguably the deepest bullpen in baseball, the loss of Muñoz will be a hit. With the ongoing coronavirus pandemic, it remains unclear when the season will begin. But when it does, San Diego will be without one of its high-octane, high-upside weapons.
"Obviously, everything's up in the air right now," Preller said. "We know we have some bullpen depth. But in general, with pitching, you know you need as many arms as possible, because injuries are unfortunately a part of it. He had a chance to make our club, be a big part of our bullpen. But for him, now, it's get ready for next year."
The Padres bullpen remains solid, with Kirby Yates at the back end, and Emilio Pagán, Matt Strahm, Drew Pomeranz, Craig Stammen and José Castillo among the primary set-up options.
As for Lawson, he sustained his injury in his final outing of the spring -- a scoreless inning against the Cubs on the evening before the regular season was officially delayed.
Lawson, the Padres' No. 16 prospect per MLB Pipeline, dealt with elbow trouble that limited him to just 27 2/3 innings at Double-A Amarillo last season. But he was a standout during the Arizona Fall League and had turned some heads in Peoria before his injury.
It sounds as though Lawson, who was slated to open the season at Double-A, took his past elbow trouble into consideration when he made his decision to opt for surgery.
"It looked like he was ready to take a real step -- from what we saw in the Fall League and some of the early outings he had on the back fields," Preller said. "But, again, he's got to be healthy. ... That was a big driver behind his decision to go ahead and get this done. He could've continued to do what he was doing -- rehab it and hope. But from his standpoint, we just wanted to get it taken care of and put it behind us."