PEORIA, Ariz. -- The Padres built a roster full of established big league regulars, meaning there isn't much sense in reading too deeply into spring results. These guys have been there, done that.

But -- for various reasons -- the Padres will be keeping a close eye on these six players this spring. You should, too.

1. Dinelson Lamet
The only established star on this list, Lamet is worth watching for one important reason: his health. The Padres are cautiously optimistic about where Lamet stands. But there are still several important hurdles to clear as he works his way back from the right elbow injury that forced him to miss the 2020 postseason.

The first of those hurdles comes Tuesday, when Lamet is slated to face live hitters for the first time since his injury. He's expected to throw a simulated inning on a Peoria Sports Complex back field. It's a noteworthy step, and it should go a long way toward setting his spring timeline.

No matter what happens Tuesday, the Padres will take things slowly with Lamet. But once he begins facing hitters and deploying his trademark slider with regularity, the Padres will feel a lot more comfortable with the health status of arguably their most electric starter.

2. Ha-Seong Kim
Kim notched his first hit in his fourth spring at-bat on Monday in a 1-0 loss to the Cubs, but that's a bit deceiving. In each of his first three trips to the plate, Kim drove the ball with authority to the outfield. His first swing on Sunday might have left the yard without a fierce wind blowing in.

"If you like line drives, I guess it's good," Padres manager Jayce Tingler said with a wry grin. "He's had four plate appearances and four barrels. He's off to really good start."

The 25-year-old infielder raked for seven seasons in Korea, but there were questions about how well he'd handle big league pitching -- particularly big league velocity.

It's early, and Kim has yet to face any true fireballers, but he seems to be handling the transition just fine. The Padres expected a minor acclimation period. But they've always felt Kim's quick hands and excellent athleticism would translate to the big leagues.

3. MacKenzie Gore
It’s an important month for Gore, whose highly anticipated callup never came last season as he struggled with command and mechanical issues at the team’s alternate training site. The Padres think he’s put those troubles behind him, and Gore backed up those claims with an impressive simulated game on Saturday. He faced seven hitters, striking out three and allowing just one baserunner -- a leadoff walk to Manny Machado.

With the return of a 162-game schedule and question marks about Lamet's health, the Padres are looking for their young starters to provide rotation depth -- Gore, in particular. He gets the ball for his first Cactus League start on Thursday against Texas.

4. José Castillo
Like Lamet, Castillo is worth watching because of questions about his health. He's pitched only two-thirds of an inning over the last two seasons because of various ailments -- including a left flexor strain, a left lat strain and a left middle-finger injury.

But with Castillo, there are other question marks, too. Most notably: If he's healthy, can he regain the form that made him one of the league's most dominant rookie relievers in 2018? In 39 career big league innings, Castillo owns 54 strikeouts. Those numbers aren't an aberration. He owns a high-octane fastball and a wipeout slider that had some Padres officials wondering whether he was closer material upon his 2018 breakthrough.

Injuries have prevented Castillo from reaching that ceiling. It's probably fair to expect some rust when he returns, and Castillo has options, so he might open the year in the Minors. But Castillo's upside remains as high as anyone in the Padres' bullpen.

5. Anderson Espinoza
When the Padres revamped their farm system in 2016, it wasn't Fernando Tatis Jr. or Chris Paddack or even Adrian Morejon who grabbed the biggest headlines at the time. It was right-hander Anderson Espinoza, the return in the deal that sent Drew Pomeranz to Boston.

Formerly the team's top prospect, Espinoza hasn't pitched since that fateful 2016 campaign. He underwent Tommy John surgery in '17, then again in '19, and he's only now returning from the second rehab process. It's worth remembering Espinoza is only 22 years old.

For all the bad luck with his health, Espinoza's upside remains tantalizing. On Tuesday, he faced live hitters for the first time this spring and recorded strikeouts of Tommy Pham and Jake Cronenworth to go along with a pair of walks. His fastball remains electric, and his curveball downright nasty (when he commands it).

Espinoza may no longer viewed as a long-term rotation piece. But the Padres feel there still might be plenty of value to extract from him as a high-octane bullpen weapon.

6. CJ Abrams
Three springs ago, a highly touted infield prospect arrived at his first Padres camp with no chance of cracking the big league roster. But Tatis made a huge impression anyway that spring, laying the groundwork for a callup the following season.

Can Abrams do the same this year? The Padres seem determined to give him a chance. Abrams -- MLB Pipeline's No. 8 overall prospect -- relieved Tatis at shortstop on Sunday, and he started at second base on Monday. He's looked sharp defensively, but he's still in search of his first spring hit.