Four days after signing a three-year, $15.025 million deal with the Ravens, offensive tackle Austin Howard still hasn’t practiced with his new team and it isn’t clear why.

“Just like I said yesterday, the same answer as yesterday, it’s in the trainer’s hands,” Ravens coach John Harbaugh said after Tuesday’s training camp practice, the last full workout before Thursday night’s preseason opener against the Washington Redskins.

Howard, 30, had surgery in January to repair a torn labrum and rotator cuff in his shoulder. The Ravens signed him about a week after he was released by the Oakland Raiders on July 28. Howard took a physical for the team before the deal became official. The contract includes a $3 million signing bonus, a $1.525 million base salary this season and option years in 2018 and 2019.

It isn’t clear whether Howard’s absence is a result of his offseason shoulder surgery or another injury problem cropped up in recent days. Harbaugh said after Saturday night’s practice at Navy that Howard was going to practice Monday, but he has not been on the field.

“I don’t have any expectations for that kind of stuff,” Harbaugh said. “You try to do what’s best for the players and what’s best for the guys and getting them ready to play. That’s in their hands. That’s in their ballpark.”

Howard won’t play in Thursday’s game, but the Ravens would certainly like to get him onto the practice field as soon as possible so he can start building chemistry with the rest of the offensive line.

Asked whether he had a timeline for his return, Harbaugh said, “I don’t have anything to add to it, really.”

Campanaro battling for spot: With 11 other wide receivers on the roster and a similar glut of players in competition to return kicks and punts, Michael Campanaro knows there is a crowded battle for one of 53 coveted spots on the active roster, which will be finalized Sept. 2.

And the 26-year-old Clarksville resident and River Hill graduate has been limited to 11 games over the past three years mainly because of injuries, including a herniated disk in his back and a strained calf.

But Campanaro said he is not worrying himself about his place on the roster.

“I don’t feel any pressure,” he said. “I just come out every day and play the game that I love. I’ve got a passion for the game, and I just want to get better. Injuries for me are part of the game. I’ve been injured more than others, but I’m healthy now and anytime that I’ve been out here playing, I’ve been making plays. So I’m confident in my ability. Just going to keep making plays.”

Since being activated from the physically unable to performance list July 31, Campanaro has participated in every practice and showed he’s fully recovered from the toe injury that sidelined him through much of the offseason minicamps.

Along with getting the first repetitions at punt returner, he has also been used in the slot with the first-team offense.

“Wherever they put me, I’m just going to come out here and play,” Campanaro said after a recent practice. “I’ve got a passion for the game, I love playing. If I’m with the ones, twos or threes, I’m going to be out here competing. There’s great guys on all levels, and it doesn’t really mean anything in training camp. It’s just great to be back out here playing.”

Harbaugh noncommittal about Thursday: Harbaugh said Monday that he expected quarterback Ryan Mallett to play “pretty extensively” in Thursday’s preseason opener. He was noncommittal about the rest of his starters.

“We’ll work it out as we go. We’ll see,” Harbaugh said. “Some guys will play, some guys won’t. [You] just have to play it by ear. We have a plan, but I’m just not really into it right now — as far as sharing it. It can change. It can change. We have a plan until the shooting starts, then plans change. All right?”

Harbaugh is traditionally conservative in playing his starters in the first preseason game. It will be interesting to see whether he’s even more cautious this year, given the number of injuries the team has endured in training camp so far.

As it is, the Ravens have a number of starters, or at least top backups, who have either not been practicing or limited to individual drills. That list includes quarterback Joe Flacco, wide receiver Breshad Perriman, offensive linemen Howard, Marshal Yanda and Alex Lewis, and cornerbacks Marlon Humphrey and Maurice Canady. Those players are not expected to play Thursday.

Redskins coach Jay Gruden told reporters Tuesday that he’s still deciding how much he’ll play his starters.

End zone: Harbaugh had no updates on the status of Flacco and Humphrey. Both Humphrey and Lewis have missed five consecutive practices. … Harbaugh praised second-year defensive end Bronson Kaufusi, saying he’s “never seen a guy work harder.” Kaufusi missed all of last season after he broke his ankle in training camp. … Former Ravens cornerback and return man Asa Jackson signed Tuesday with the San Francisco 49ers.

jeff.zrebiec@baltsun.com

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Baltimore Sun reporter Edward Lee contributed to this article.