PEORIA, Ariz. -- The Padres couldn't escape camp in Arizona without a very troubling injury scare on getaway day.
Promising right-hander Dinelson Lamet exited his outing against the Mariners in the second inning Sunday with pain in his pitching elbow and, according to a source, will begin the season on the disabled list. Earlier that morning, Lamet had been named the club's No. 2 starter, slated to pitch Friday against Milwaukee.
No structural damage was found and the hope is that he'll return sometime in May. Lamet first felt it on a second-inning slider to Mariners right fielder Mitch Haniger, and he exited one pitch later after meeting with a trainer on the mound.
"Right before the season starts, you don't want to lose one of your best starting pitchers," said Padres manager Andy Green. "Hopefully he's not out for long, but usually you walk off the mound and your elbow hurts, it's not a good thing."
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The Padres expected big things out of Lamet in 2018, his second season with the club. Last year, the 24-year-old right-hander posted a 4.57 ERA over 21 starts while setting a club rookie record with 10.9 strikeouts per nine innings. This spring, he added a biting curveball to his already impressive fastball/slider mix.
"Any time you pull one of your main guys out of a game at any point in Spring Training, it's concerning," Green said. "The last tuneup outing before the season? Yeah, it's very concerning. We'd love to have him, he's a big part of what we plan on doing."
If Lamet isn't available, the Padres have a handful of options capable of filling his spot in the rotation. Right-hander Christopher Young appeared destined to serve as long man in the bullpen. He pitched Sunday in relief of Lamet. Left-hander Robbie Erlin, who missed all of 2017 with Tommy John surgery, is another option.
The most intriguing candidate might be 24-year-old lefty prospect Joey Lucchesi. Out of nowhere, he thrust his name into the rotation mix with an excellent spring in which he posted a 1.54 ERA over four outings.
A 2016 fourth-round Draft pick out of Southeast Missouri State, Lucchesi has been dominant at every level. He owns a 1.99 ERA in two professional seasons and currently rates as the club's No. 9 overall prospect. Following Lucchesi's reassignment to the Minors on Saturday, Green raved about his performance.

"There was real conversation of taking him right out of camp, the way he threw the baseball," Green said. "It could be an injury, it could be anything that puts him back in the mix. He's not far off."
The Padres remain hopeful those words won't prove prophetic. The schedule could provide a respite, if they choose to use it. With an off-day Sunday following the opening series against the Brewers, the Padres wouldn't need a fifth starter until April 6 in Houston.
"There is a little bit of flexibility," Green said. "We'll go in and explore what's best for us."