Everything you need to know about Luis Severino's shoulder injury

WASHINGTON -- Exactly one week before what would have been the second Opening Day start of his career, Luis Severino was lightly throwing inside the New York Yankees' spring training ballpark in Tampa, Florida.

After finishing his 50 tosses on flat ground, he didn't go anywhere near a mound. From a throwing standpoint, the pitcher did nothing else that day.

For the foreseeable future, he will have more days like that. The Yankees' ace, who last month signed a four-year, $40 million contract extension, will be spending the first week of the season -- and significantly longer -- more than 1,000 miles away from Yankee Stadium.

He can thank a shoulder injury for that. Severino was sidelined nearly three weeks ago, and the pain put a pause in both the the right-hander's plans as well as the plans that the Yankees had for the front end of the rotation. Adjustments had to be made.

But with the season opener now days away, one of the Yankees' most pressing concerns is this: How long will they be without Severino? And will the star be his old Cy Young-contending self when he returns?

To answer those questions, it's best to first understand what exactly he's dealing with.

While warming up minutes before his afternoon start against the Atlanta Braves on March 5, Severino felt what he described as a "pull" in his right arm as he tried snapping off a slider to Yankees catcher Gary Sanchez. Severino said it was a surprising twinge of pain, considering how fine he had previously felt throwing sliders earlier in the spring. As soon as he hurt his shoulder, Severino said he stopped his warm-ups. He was immediately evaluated.

"That's 100 percent very important," said Stephania Bell, ESPN's injury analyst, a board-certified orthopedic clinical specialist and physical therapist. "Because if he keeps trying to push it and it turns into something more substantial, a more significant injury, you can't retreat from that."

It's important to note Bell has not worked with Severino and has not done her own evaluation of his shoulder. Relying on her experience, reporting and published reports about Severino's injury, however, she can assist in analyzing his path forward.

The defining piece of Severino's evaluation was an MRI that revealed rotator cuff inflammation. Of the types of injuries a pitcher could receive to his rotator cuff, inflammation might be the most favorable. Had the MRI revealed a strain or a tear, Severino could be facing a much steeper climb to getting back on the mound. Tears, after all, have effectively ended some pitchers' careers.

The reports on Severino from Yankees manager Aaron Boone and general manager Brian Cashman have been positive. The fact that he has begun making early strides in his recovery has been promising, too.

On Sunday, Severino graduated from the 50-foot throws he made in the middle of last week to completing 90-foot throws. Monday, he made throws from up to 120 feet away.

"That all went well," Boone reported ahead of Monday's exhibition game in Washington. The day before, he noted Severino was "moving in the right direction." The Yankees have not yet said when he will throw off a mound, but that is likely to happen soon.

These are important steps, especially considering a week ago Severino still was resting his shoulder. Right after the injury was diagnosed, he began a cycle of anti-inflammatories and was shut down. For two weeks, he didn't pick up a baseball.

Despite his recent progress, there's reason for the Yankees to be guarded in their optimism.

"Anytime it's a thrower's shoulder, you get nervous because there's so many nuances to the health of a pitcher's shoulder. It's the uncertainty that makes you nervous," Bell said. "The thing you would worry about is that if it doesn't resolve 100 percent as far as throwing, and you're getting into a long season, that sets him up for something more significant down the road.

"That's why you see the team being very cautious on the return: 'Let's make sure this is 100 percent behind us.' And if he really feels good, and they bring him back slowly and he feels fine, then it may be exactly that -- a little blip on the radar and not anything more."

Four letters spell out Severino's hope: ASAP. But as much as the 24-year-old would like to get back into the rotation as quickly as possible, he's well aware of how delicately he must approach his comeback.

"This is the game that I love, and I want to be there for the team," he said when he was first hurt. "It's going to be tough for a little bit, but after that ... it's better it happened now than in midseason or at the end of the season."

The when is indeed important. Since he hadn't yet appeared in a game (the early March start was slated to be Severino's first of the spring), the Yankees were essentially able to revert the ace's rehab calendar as if the start of his recovery were the start of his spring training. Expect his new spring training to last at least five weeks, going back to the day last week when Severino threw on flat ground for the first time.

He'll likely be making multiple starts in minor league games before he gets to crack the Yankees' active roster. Since the Yankees would want to manage his rest and get him in a rhythm that will allow him to eventually rejoin their rotation, they are expecting it to be just after May 1 before he's back in big league pinstripes.

With Severino out at least the first month, the Yankees will be tweaking their rotation to give a few young pitchers opportunities to serve as fill-ins.

For the first five days of the season, they will go with a four-man pitching staff: Masahiro Tanaka, James Paxton, J.A. Happ and Domingo German. Tanaka replaces Severino as the Opening Day starter, and Jonathan Loaisiga is expected to slide into the fifth spot in the rotation once the first five games of the season pass. (The Yankees are keeping that slot open as CC Sabathia serves a five-game suspension.) Luis Cessa also is on the active roster and can come out of the bullpen if the Yankees go with an "opener" during their first turn or two through the rotation. Boone has already said that's a possibility.

Tanaka makes an interesting option for temporary ace. Although he's winless in three previous Opening Day starts, he's also 13-4 with a 3.38 ERA in March and April in his career.

There's no reason to believe Severino wouldn't return to his typically dominant form once he makes his recovery. If his shoulder is healthy, he can pitch like he did before. So barring any issues, the plan would be for him to jump back into the Yankees' rotation as soon as he's healthy and to remain there the rest of the year.

Once he returns, New York will have to get creative with its pitching depth, figuring out a way to balance the combination of Cessa, German and Loaisiga on the roster.

In addition to that trio, the Yankees could have another pitcher whose role would have to be tweaked come May. Lefty Gio Gonzalez, a 33-year-old who signed a minor league deal last week, might be part of the rotation before Severino's expected return. Gonzalez appeared in only one spring training game before the Yankees broke camp, and although he had shoddy results -- five runs, four hits and a home run in two innings pitched -- he was pleased that he was at least in the strike zone regularly. He felt that not throwing balls in the dirt or to the backstop at this early stage of his year was a promising sign.

Since it took so long for him to sign with a team, it will be a couple more weeks before Gonzalez is major-league-ready. And if he's not prepared to pitch by April 20, he and the Yankees can opt out of the one-year deal.

In terms of Severino, will he have to be built up slowly once he gets back to the Bronx? Will he receive fewer innings at the start of his season? Will he ultimately miss a start or two late in the season to avoid overusing his arm ahead of October?

Those questions will be answered in time. For now, the Yankees will continue to closely monitor Severino's shoulder.

"When something's in somebody's history, you can't remove that. You have this awareness of, 'OK, this is his history,'" Bell said. "But I don't see them being overly alarmed throughout the course of the season if he comes back and he's fine. It really could be just this one thing and then we don't hear about it again."

Then again, because it's a shoulder injury, there's always the chance we could.

"Certainly if we get in a couple months deep and he's cruising along and then all of a sudden he's like, 'Yeah, I feel a little something,' they're going to be more responsive to it maybe just because of the fact that he had a prior [injury]," Bell said. "But I would say everything about the approach is adjustable, and what they're trying to avoid is that they just signed this guy for this big-money deal.

"They're trying to preserve the life of his arm for a career. They don't want to do anything foolish and rush him."