CLEARWATER, Fla. -- The Phillies' starting rotation remained very much in flux Friday with the announcement that right-hander Jerad Eickhoff, expected to be the team's No. 3 starter, will be out six to eight weeks with a strained lat muscle. He will begin the season on the disabled list.
Recently acquired Jacob Arrieta has provided depth to the rotation and hopes to be ready for the start of the regular season, with Aaron Nola getting the Opening Day nod.
Eickhoff (4-8, 4.71 ERA last season) missed some time with back stiffness and nerve irritation in his pitching hand during 2017.
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Phillies manager Gabe Kapler said Eickhoff suffered the injury during a 3 1/3-inning appearance against the Pirates on March 9. Eickhoff, who felt discomfort on one of his final pitches of the outing, was sent back to Philadelphia, where the lat injury was diagnosed. It's in the right lat, just below the armpit.
Kapler said he didn't believe it was a carryover from last season's physical woes, calling it an "independent lat injury."
"There might be a blessing in disguise here," Kapler said at Spectrum Field. "We're always thinking about keeping guys healthy and strong and limiting their total innings count.
"Those are things that are always on our mind, so it's possible the innings are limited on the front end and then in September, October, he's strong and healthy and prepared to go through a full season."
In Eickhoff's absence, right-handers Vince Velasquez and Nick Pivetta should have enhanced roles. The immediate question: Who will be the No. 5 starter? Candidates include Zach Eflin (who starts Saturday against the Braves), Ben Lively, Mark Leiter and Tom Eshelman. All are right-handers.
"We have a lot of candidates to take the ball at the big league level," Phillies general manager Matt Klentak said.

Eickhoff, 27, joined the Phillies in 2015 as part of the deal that sent Cole Hamels to the Rangers. Eickhoff was 11-14 with a 3.65 ERA in 197 1/3 innings during 2016, but injuries limited his effectiveness last season.
Klentak said he's confident that Eickhoff's current injury will be a momentary setback. He said Eickhoff could be ready for Major League action in May.
"The good news is it seems like it's pretty mild," Klentak said. "He should recover from it and be absolutely fine with it, but it's going to take a little while to recover. The timing of it is the tricky part because he wasn't fully stretched out to begin with.
"We were in the early stages of Spring Training when he last pitched. Once he comes back and starts throwing again, he's going to have to work himself back into throwing shape and get himself all stretched out. That's going to take a little bit of time."
Meanwhile, as the Phillies continue to arrange their rotation, more attention will be focused on Arrieta, a free-agent acquisition. Arrieta is scheduled to pitch Saturday in a simulated game at Clearwater's Carpenter Complex, the first step in an accelerated process to prepare him for the season.
If Arrieta needs more time, the Phillies might consider a four-man starting rotation. Arrieta had his first bullpen session on Wednesday.
"How quickly we can get [Arrieta] up to speed and how we work him into the rotation will have an impact on that," Klentak said.