Ravens quarterback Lamar Jackson missed his second straight practice Thursday, heightening concerns that injuries could sideline him for Sunday’s game against the Denver Broncos.

Jackson, who on Thursday was named the AFC Offensive Player of the Month, missed practice Wednesday, which coach John Harbaugh characterized as a “rest day.” He was later listed on the team’s injury report with knee and back designations.

Jackson, who was seen in the locker room after practice Thursday, hasn’t missed a start because of injury since 2022. Backup quarterback Josh Johnson hasn’t started since 2021.

“It is what it is,” offensive coordinator Todd Monken said Thursday. “Josh can use the work. ... Like any other position, you go to work and guys have to still function around him.”

Jackson played every offensive snap of the Ravens’ 29-24 loss Sunday to the Cleveland Browns but appeared to be in discomfort in the locker room afterward. Harbaugh indicated after practice Wednesday that the Ravens’ compressed schedule — after Sunday’s game in Baltimore, they face the Cincinnati Bengals on “Thursday Night Football” — was a factor in Jackson’s availability.

“He’s been playing great, and we’ve got a lot of football in front of us here,” Harbaugh said. “We’ve got [a] game, quick game, another big game coming up, so that was warranted today.”

The Ravens also have injury concerns along their defensive line. With Michael Pierce on injured reserve, Brent Urban sidelined by a concussion, and Broderick Washington (knee) and Travis Jones (ankle) missing practice Thursday, Nnamdi Madubuike was the only lineman on the team’s 53-man roster who was practicing.

Rookie running back Rasheen Ali, meanwhile, returned to practice for the first time in two weeks. He’d been sidelined by an ankle injury and was limited Thursday. Cornerback Arthur Maulet, sidelined by a neck injury Wednesday, was also back as a full participant.

Marlon Humphrey (knee) was still limited in practice, but fellow starting corner Nate Wiggins (shoulder/illness) was upgraded from limited to full participation.