HOUSTON -- Starter Luis Severino was diagnosed with a Grade 2 lat strain that will prevent him from throwing a ball for six weeks, the team announced prior to Tuesday’s game in Houston.

The injury is separate and independent from the rotator cuff inflammation Severino sustained during Spring Training. The lat strain emerged at some point between the diagnosis of that injury and his ongoing rehab process.

"I don’t know if relief’s the right word, but it’s a little bit like, 'OK, now we know what it is,'" manager Aaron Boone said after the Yankees’ 6-3 loss to the Astros. "A little relief that it’s not a surgery thing. There’s a little comfort in knowing this is what it is. It appears to be treatable. It’s going to take some time and hopefully we’ll get a healthy, strong and fresh Sevy back for a good portion of the season."

Severino had progressed to throwing at 130 feet but never felt good enough to start throwing off the mound, which drew concerns from Boone and the medical staff, who sent Severino back to New York on Monday to be examined by Dr. Chris Ahmad, who oversaw the MRI process.

The Yankees will now be tasked with replacing Severino at the top of the rotation for longer than they had originally hoped. Beyond internal options, they could look outside the organization. Free-agent lefty Dallas Keuchel, who won the Cy Young Award in 2015 and pitched to a 3.74 ERA last season for the Astros across 204 2/3 innings, is still available.

Andujar to play catch

Miguel Andújar attracted some attention from reporters in the clubhouse a few hours before first pitch on Tuesday, for no other reason than he was wearing batting gloves and gripping a bat while fidgeting at his locker.

Was he on his way out to hit?

“No,” Andujar said with a grin, speaking through an interpreter. “I like the sensation of having a bat in my hand. It’s been a while, so I don’t want to forget the feeling.”

Andujar is scheduled to play catch on Wednesday, a small but significant step toward what the Yankees hope will be a recovery speedy enough to get him back on the field soon. Right now there is no timetable for a return, nor have there been any promises made that he won’t need surgery to repair the damage sustained when he slightly tore his right labrum diving back into third base during the Yankees’ season-opening series with the Orioles.

The third baseman has been on the injured list since April 1; his light throwing session on Wednesday will be his first real test.

“Hopefully it’s a big step,” Boone said. “That potentially tells us a lot in how he’s able to respond. I don’t think they’re going to stress him out too much tomorrow. Hopefully he’ll get some encouraging news when he does go through that initial step of playing catch. We’ll see where we’re at tomorrow.”

Andujar said his shoulder feels better now than when he first sustained the injury. He’s mostly focused on sticking to his rehab plan to strengthen the shoulder and said that he just feels the general soreness that normally comes after working muscles that haven’t been awakened in a while.

“I’m stretching a lot,” he said. “I’m much better.”

The hope, obviously, is to avoid surgery, but he stopped short of gauging his optimism in that regard.

“I’m following the protocol that we have in place to heal and recover,” he said. “I’m following every single step of it and doing everything I’m supposed to. But we’ll have to wait and see how I’m going to feel as I go through the whole process.”

Loaisiga sent down

After Tuesday's game, the Yankees optioned Jonathan Loaisiga to Triple-A Scranton/Wilkes-Barre. Loaisiga allowed two runs on four hits with two walks and five strikeouts over three innings in his start against the Astros. He threw 71 pitches. On Wednesday morning, the club announced they recalled right-hander Joe Harvey from Scranton/Wilkes-Barre.