SCOTTSDALE, Ariz. -- You can add third baseman Josh Rojas to the list of D-backs players who will open the 2022 season on the injured list, joining shortstop Nick Ahmed and outfielder Jordan Luplow.

Rojas, who was expected to be the starter at third base, was diagnosed with a Grade 2 strain of his right oblique muscle and will be out a "matter of weeks," according to manager Torey Lovullo.

The injury impacts Arizona's Opening Day roster in a couple ways.

Unless the D-backs make a waiver claim or a trade, they are left looking at internal candidates Drew Ellis, Jake Hager and Sergio Alcántara at third base. Defense will be the deciding factor in who takes Rojas' place.

"Somebody will step in and get that opportunity," Lovullo said. "The most important feature of his replacement will be somebody that's going to pick up the baseball and operate at full speed while they play defense. That's top priority for me right now."

The fact that Rojas has been hurting for a couple days also explains why Lovullo has left open the possibility that rather than carry 15 pitchers and 13 position players, the D-backs may in fact carry 14 of each.

Speak up
Rojas' injury began as something he felt slightly and thought he could work through. But then this past Thursday, he swung at a fastball from Padres right-hander Chris Paddack down and away, and Rojas felt it worse. He underwent an MRI on Friday that showed the strain.

Lovullo used the incident as an opportunity to remind his players that they need to speak up immediately when they feel something, rather than trying to play through it.

Rojas, though, felt he was still competing for a job and thought he could do it. He talked to Ahmed after the diagnosis and the veteran shortstop reiterated to Rojas that players have to try to nip minor injuries like that in the bud quickly.

"I assumed that this was another one of those things that was another little nick or a bruise," Rojas said. "I was doing all my activation and keeping it to a minimum and I would be able to play through it and try to earn a job. I was playing for a job this year, in my eyes. I was trying to win third base. I was going to do anything I could to get myself on the field."

Bumgarner to start opener
On Sunday, Lovullo made official what had been obvious for weeks -- Madison Bumgarner will start Opening Day against the Padres on Thursday at Chase Field.

"The one thing I want to make sure that I say is I want to acknowledge how hard he has worked and what kind of shape he came in here in," Lovullo said. "Compliments to him for the work he did during the [lockout], and he came in here and earned this moment."

This will be Bumgarner's third straight Opening Day start in a D-backs uniform.

Special guest appearance
Former Red Sox second baseman Dustin Pedroia addressed the D-backs on Sunday morning at the request of Lovullo, who was Boston's bench coach and interim manager during part of Pedroia's time there.

"It was good to see Dustin today," Lovullo said. "Dustin delivered a great message to our team today, and I didn't have any doubt that he would. He talked about preparation, focus, effort, and then the ability to win and what it means to win inside of a day."

Herrera to be backup catcher
Catcher Juan Graterol, infielder Matt Davidson and outfielder Braden Bishop were reassigned to Minor League camp. That means that Jose Herrera has won a spot on the D-backs' roster as a backup catcher.

Carson Kelly will start behind the plate, with Herrera backing him up. Daulton Varsho will get most of his work in the outfield, but he will also see some time at catcher.