CLEARWATER, Fla. -- The Phillies’ pitching staff is likely set with Opening Day four days away.

Phillies left-hander Ranger Suárez is expected to open the season on the 15-day injured list, pushing right-hander Taijuan Walker into the rotation. Left-hander Matt Strahm’s left shoulder is fine, although his final check will come Monday when he pitches in the Grapefruit League finale. The Phils on Sunday claimed right-hander Carlos Hernández off waivers from Kansas City. He will join the bullpen.

To make room for Hernández on the 40-man roster, right-hander Tyler Phillips was designated for assignment.

Phillies manager Rob Thomson said on Sunday’s TV broadcast that Suárez will open the season on the IL. After the Phillies’ 4-2 Grapefruit League victory over the Tigers at BayCare Ballpark, however, Thomson said the Phils “expect Ranger to go on the IL.”

Suárez has not pitched since March 15 because of a sore lower back. He played catch Saturday and Sunday, but considering his importance to the team and his history of back issues, there is no reason to rush him.

“We want to take care of him,” Thomson said. “We don’t want this thing to linger. So if we do officially IL him, we don’t think it’s going to be long.”

The Phils can backdate Suárez’s IL stint three days before Opening Day. He would be eligible to be activated as early as April 8 in Atlanta.

If that happens, he would miss only one start.

Walker is expected to start on April 3 against the Rockies at Citizens Bank Park. He had a good spring, until his start last week against the Yankees. His four-seam fastball has averaged 92.4 mph after averaging 89.3 mph last spring. His splitter has been much better.

The Phillies believe Walker should compete better this year than last, when he posted a 7.10 ERA.

“His stuff’s better, flat out,” Thomson said.

The Phillies on Sunday morning optioned right-hander Michael Mercado to Triple-A Lehigh Valley, leaving Phillips as the only remaining pitcher in camp without a job. Phillips had a 7.59 ERA in 10 2/3 innings this spring, striking out 14 and walking seven. But Phillips finished strong, striking out six in his final two outings.

Phillips looked to have the final spot in the bullpen, until the Phils claimed Hernández.

“We just think maybe there’s a little bit of an upgrade here,” Thomson said. “It’s a guy that’s familiar with pitching out of the bullpen.”

Hernández is 7-19 with a 4.95 ERA in 150 career appearances (25 starts) with the Royals. He had a 6.97 ERA in 10 1/3 innings this spring.

Hernández has an elite fastball that averages 97.9 mph. He has a slider, curveball and splitter that generates swings and misses.

“He’s got a great arm,” Thomson said. “He’s pitched two innings multiple times in Spring Training. So he’s a two-inning guy.”

But Hernández’s elite stuff hasn’t translated into consistency in the big leagues, which is why he ran out of chances in Kansas City. Of 277 pitchers who have thrown 200 innings or more the past four seasons, Hernández’s 11.3 percent walk rate is tied for 12th highest in baseball.

In Philly, Hernández will be used mostly as a long man. He is unlikely to pitch in high-leverage situations unless absolutely needed.

The Phillies have one more roster decision to make before they fly to Philadelphia on Monday, other than formally placing Suárez on the 15-day IL. After telling Johan Rojas that he made the team, the Phillies must tell Kody Clemens or Buddy Kennedy if they got the final spot on the bench.

Both are out of options.

Lineup shuffle

The Phillies’ lineup hasn’t been decided. Thomson has had both Trea Turner and Kyle Schwarber hit leadoff this spring.

It might continue that way into the season, too.

"It could be, against a lefty, Turner leads off, against a righty, Schwarber leads off,” Thomson said. “But those top four guys remain the same four guys."

Those four guys are Turner, Schwarber, Bryce Harper and Alec Bohm.

“Hopefully, we’ll find out soon,” Thomson said about the lineup. “How guys adjust to it, that’s a big question. Because I know that guys like being in the same spot every day. It’s just hard to do that every day. But we want to figure out if we can maximize our offense.”