FORT MYERS, Fla. -- It looks like it will be a lost Spring Training for Bryan Mata, Boston’s No. 4 prospect (and top pitcher) according to MLB Pipeline.

The righty starter, who is in big league camp for the second straight year, has been diagnosed with a slight tear in his UCL.

At this point, the Red Sox are taking a conservative approach and not recommending Tommy John surgery.

“We’re going to shut him down,” said Red Sox manager Alex Cora. “The way we’re going to go with him is [with] treatment. We feel, the doctors and the physicians feel that it’s small enough that we think with treatment and doing that, he should be fine. Obviously, it’s going to take some time.

“There’s no timetable. There’s going to be a few checkpoints throughout the process. With his discipline and following everything that we are set to do, the hope is for him to come back. Like I said, no timetables. As you guys know, he’s very important for us. It’s a tough [loss], but at the same time we do believe he’s going to bounce back and he’s going to be OK.”

Of course, there’s no guarantee Mata will avoid surgery, but that is the hope.

“Obviously we have to be patient and see how he reacts,” said Cora. “We don’t feel comfortable of course because it’s the UCL. We just have to be patient and he has to be patient. He’s young enough where probably everything is going fast for him right now. But he is mature enough to understand these things happen over the course of your career. He did an amazing job in the offseason to get in shape and get his arm where it’s supposed to be. It’s an obstacle in his career, but we do feel he is going to bounce back and he is going to be OK.”

The 21-year-old Mata, who hails from Venezuela, was signed by the Red Sox as an international free agent in 2016.

In 315 innings in the Minors, Mata is 22-20 with a 3.40 ERA with 307 strikeouts. He has held opponents to a .242 average.

Mata’s best pitch is a two-seamer, which sits between 93-97 mph.

Casas could be close to action
The Sox had better news on corner-infield prospect Triston Casas, who was sent to Boston earlier this week to get tests on a non-baseball medical situation.

Casas is back in Fort Myers and going through the COVID-19 intake process, with the hope of getting back on the field in the coming days.

Considered by many to be the most intriguing bat in the Red Sox’s system, Casas could rejoin the team “over the course of the week,” according to Cora.

“Things are trending in the right direction and we’re comfortable with where this is going,” Cora added.

Casas is Boston’s No. 2 prospect and this is his first Major League Spring Training.

Numbers game
When Japanese righty Hirokazu Sawamura reported to camp last weekend, he was wearing a temporary number (22).

But now that Jackie Bradley Jr. has agreed to terms with the Brewers (according to a source), Sawamura is donning No. 19 in honor of his mentor and former Red Sox closer Koji Uehara.

• Sawamura throws bullpen session at JetBlue

In fact, Uehara, a stud for the Red Sox in their World Series-winning season of 2013, played an important role this winter in selling Sawamura on how great a place Boston is to play.

“Koji Uehara had a lot of influence in my decision-making process. He told me a lot of good stuff about the Red Sox and his experience, and he shared with me all of his experiences,” Sawamura said on Feb. 17.

Franchy takes the field
Outfielder Franchy Cordero, who was acquired from the Royals for Andrew Benintendi on Feb. 10, took the field for the first time with his new team on Saturday morning during the team’s workout.

However, Cordero, who started Spring Training on the COVID-19 injured list, was mostly just an observer.

There’s no timetable for when Cordero will play in games. However, Cora suspects he’ll be ready for the start of the season.

“I was actually talking to [strength and conditioning coach] Kiyoshi [Momose]. He’s a little bit behind physically, but with the kind of athlete he is and his physicality, actually he’s not having an off-day Monday, he’s coming here to work out with him,” Cora said. “He feels like he should be able to catch up fairly quickly.

“We have to communicate with the player and make sure he understands he doesn’t have to rush. Whenever he’s ready, he’s ready. We still have plenty of time in terms of at-bats. As you guys know, it’s not only what we do on the big field, but we have a lot of at-bats on the back field. So I’m confident that he should be catching up soon and be ready for big league games. It’s not going to take that long.”

Short Saturday
The Red Sox and Twins were supposed to play five innings on Saturday at JetBlue Park. Thanks to rainy conditions, they played just two.

Ryan Weber, projected to start the season at Triple-A Worcester, gave up four hits and two runs over two innings. The Red Sox went 0-for-6 against Twins righty Michael Pineda. The game, which started at 1:05 p.m. ET, was called just 37 minutes later.

Up next
Righty Garrett Richards, who labored in the first inning of his Red Sox debut on March 1, will try to have a sharper outing Sunday on the road against the Braves. J.D. Martinez, Rafael Devers and Hunter Renfroe are among the regulars making the trip. First pitch is scheduled for 1:05 p.m. Watch all the action live on MLB.TV or listen on MLB Audio.