Spring Training is underway -- and just as important as the players taking the field in Arizona and Florida are the ones who are in the process of making their way back to it.

Key players for teams across the Majors are recovering from injuries, and updates on their statuses are rolling in from camp Tuesday.

The following are health-related notes you should know about from today's Spring Training action, as compiled by MLB.com's team reporters and contributors.

Murphy limited but still hopeful for Opening Day

Nationals second baseman Daniel Murphy wasn't able to participate in the team's first full-squad workout for position players on Tuesday. But he continues to be optimistic that he can hit his goal of being ready for the start of the season.

Murphy hasn't been able to hit for the last several months as he recovers from the debridement and microfracture surgery he underwent on his right knee after the Nationals' season ended. He couldn't take part in Tuesday's live batting practice session, MLB.com's Jamal Collier reported.

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"You see these guys bouncing around and playing, you want to participate and be playing with your teammates," Murphy said Tuesday. "But I think it's the understanding of when the training staff lets me go and it's time to play, you only want to come off the DL once. I don't want to start playing games and then have to stop."

Murphy's baseball activities are still limited to fielding grounders from his knees, playing some catch and running on the treadmill with about 60 percent weight-bearing on his knee. Still, he said he's happy with his progress so far and knows he has to be patient. Collier reports Murphy is no longer using the crutches he had at Nationals WinterFest in December. He still feels some slight discomfort in his knee but has full range of motion.

"I'm more concerned about rushing him and him not being fully ready," Washington manager Dave Martinez said. "When we get him back, we don't want him to go back on the DL, we want to get him back for the whole season."

Martinez said last week that Murphy is still on track to return by Opening Day -- for the Nationals, March 29 in Cincinnati. The Nats plan to first slowly incorporate Murphy into Spring Training games.

Mets won't rush Conforto back

Michael Conforto is eager to get back on the field after shoulder surgery prematurely ended his 2017 season, but he and the Mets want to make sure there's as little risk of re-injury as possible before giving him the green light.

Conforto addressed his recovery on Tuesday, saying, "The timetable is fluid." Mets general manager Sandy Alderson has targeted May 1 as a return date for the 24-year-old outfielder.

"My energy is channeled into my rehab," Conforto said Tuesday, as MLB.com's Anthony DiComo reported. "Every rep gets me a little bit closer to getting back out on the field. As long as I keep that fire, I think that's what's going to get me out there and be successful and be healthy."

DiComo reports that Conforto started swinging off a tee this weekend, the latest step in his recovery process after he spent most of the offseason logging two hours of physical therapy daily.

"I want to make sure that when he's back, he's back," new Mets manager Mickey Callaway said Tuesday. "We want him to just go through his rehab routine, make sure we communicate with him along the way how he's feeling. Players always tell you they feel better than they probably are, so we're going to be aware of that. But we want him back and when he's ready, he's there for the rest of the season."

Conforto was an All-Star in 2017 and was the Mets' best hitter until he dislocated his left shoulder on a swing during a game on Aug. 24. Testing revealed a capsule tear and Conforto underwent surgery -- a choice which, according to team physician Dr. David Altchek, vastly reduces the odds that Conforto will dislocate the shoulder again.

All signs "positive" for Sanchez

Blue Jays right-hander Aaron Sanchez threw his first batting practice of the spring on Tuesday, and he showed no signs of the injuries that cost him most of the 2017 season.

Sanchez battled recurring blister issues on his pitching hand all year, and made just eight starts a year after his All-Star breakout in 2016. But he looked good throwing to a group of Blue Jays hitters including Kendrys Morales, Steve Pearce, Justin Smoak and Josh Donaldson at the team's facility in Florida, as MLB.com contributor J. Scott Butherus reported.

"In terms of how I felt and the ball coming out of my hand, there were no issues," Sanchez said. "I felt like the action was really good. My command was really good. No issues with the finger, which is a huge plus. Arm felt good. Body felt good. All signs were positive."

The 25-year-old hadn't faced hitters since July. But he reported to camp early and said Tuesday that he now feels like he's ahead of schedule.

Manager John Gibbons said that Sanchez "really looked like midseason form, and that's exciting to see. Everything came out nice and easy and really locked in. I didn't expect to see him that good."

Marisnick back from thumb injury

Astros center fielder Jake Marisnick had to watch from the sidelines with a fractured thumb as Houston won its first World Series, so he's been especially eager to get back on the field as Spring Training begins.

On Tuesday, he did just that. Marisnick faced live pitching for the first time in nearly seven months, MLB.com contributor Glenn Sattell reported, and said that his thumb -- which he fractured Sept. 13 -- is now 100 percent healthy.

"It feels good to get back in there," Marisnick said Tuesday. "It takes a couple of rounds of it and you're good to go. It's been a long time since I've been able to step on the field. So I'm excited to get camp going. I'm excited to be able to run around the field, take some swings."

The 26-year-old was having a career year before the injury, with a personal-best 16 home runs and .815 OPS thanks to a retooled swing that helped him lift the ball with more regularity. Marisnick said Tuesday that he hasn't lost that new swing even with the long layoff, and now it's just a matter of getting his timing back with more reps in the batter's box.

"I've been hitting a lot," Marisnick said. "Hitting is all about timing. It's something that comes with repetition. Obviously, I'm a little bit off on timing, as is everybody here, for not seeing a pitch in a while."

Lewis sidelined after minor knee surgery; No firm timetable for Erasmo

Mariners top prospect Kyle Lewis, ranked the No. 70 overall prospect in baseball by MLB Pipeline entering the 2018 season, had arthroscopic surgery on his right knee about a week and a half ago, MLB.com's Greg Johns reported Tuesday.

Lewis is not expected to return to the field until the end of April. The 22-year-old outfielder is not yet at the team's Minor League mini-camp, but he will report on Thursday. General manager Jerry Dipoto said the club should know more then.

Lewis has had ongoing issues with his knee after major surgery to repair a torn anterior cruciate ligament and medial and lateral meniscus following a 2016 home-plate collision. The Mariners are hoping this cleanup procedure will alleviate those issues.

"There was kind of a floating piece of bone that was pinching off or creating a problem," Dipoto said Tuesday. "It explains why he was having so much pain. Hopefully we are able finally to determine the source of the irritation and move forward in a productive way."

Dipoto also addressed right-hander Erasmo Ramirez's status. The 27-year-old was diagnosed with a strained right lat muscle on Sunday, and Dipoto said Tuesday that the Mariners aren't certain that Ramirez will be ready for the start of the season. For now, Ramirez has been shut down for two weeks, and the best-case scenario is he can start throwing after that.

"Hopefully we caught this one early enough that it's short to mid-term," Dipoto said. "We don't know yet. We're hoping in two weeks we get a thumbs-up and he's ready to roll. But that's not a slam dunk. Then we have to take it day by day."