SANTA CLARA, Calif. — For the second consecutive week and the fourth time in the first six games, Mac Jones is expected to start at quarterback for the San Francisco 49ers on Sunday.

Jones was limited in practice all week because of left knee and oblique ailments and is listed as questionable for Sunday. Despite that, he is slated to start against the Tampa Bay Buccaneers, as coach Kyle Shanahan said on KNBR radio Thursday.

“Pretty much already have [said he will play],” Shanahan said Friday, referring to his radio interview. “But you’ve got to put it that way if there’s any doubt at all. … It’s all recorded. I don’t think I have to repeat my answer.”

Jones’ fourth start comes as starting quarterback Brock Purdy continues to deal with a toe injury he suffered in Week 1 and aggravated in Week 4. Purdy did not practice this week and was officially ruled out Friday.

Jones did not do any strenuous throwing in Thursday’s practice, saying afterward that he was “saving” throws so he could be better prepared for Sunday’s game. He did, however, do some throwing Friday.

Jones expressed confidence he’d be able to play against the Bucs but acknowledged that much would depend on how the rest of the week plays out.

Jones’ knee injury happened in a preseason game against the Las Vegas Raiders, and though he recovered, he aggravated it in Week 3 against the Arizona Cardinals. He then strained his oblique on San Francisco’s final offensive snap against the Rams.

But Jones and the Niners had a few extra days to recover after the Thursday night game and then put in a plan to limit his workload this week with an eye toward having him available in Tampa for a clash of 4-1 NFC teams.

“I believe if you can protect yourself, that you should be out there and playing,” Jones said. “A lot of guys are working through stuff. That’s the NFL, and I’ve learned that you just got to be able to go out there and protect yourself and play. … You can be tough and have a good attitude and work through the mental and physical stuff, and that’s all you can ask for really.”

Much like last week against the Rams, Jones and the Niners’ offense will enter this game with a cobbled-together crew of pass catchers available at tight end and wide receiver.

That’s because wideout Ricky Pearsall will miss his second straight game with a right knee injury. Jauan Jennings is considered more of a game-time decision as he practiced on a limited basis Thursday and Friday with rib and ankle injuries.

In addition to Pearsall and possibly Jennings, the 49ers are still without tight end George Kittle (hamstring) and receivers Brandon Aiyuk (knee) and Jordan Watkins (calf).

That leaves the Niners once again expected to turn to a group that includes receivers Kendrick Bourne and Demarcus Robinson and tight ends Jake Tonges and Luke Farrell to fill the void.

Against the Rams, it was Bourne who emerged as Jones’ top target as he posted a career-high 142 yards on 10 receptions.

“He just gets better every week,” offensive coordinator Klay Kubiak said. “He’s a gamer. You see a guy who’s still learning to grasp our offense schematically, but he gets better every week. He’s such a joy to be around because he’s all-in. He’s got a great attitude. He works at it. I think he’s a guy, the more he is out there, the more he is going to help us. And so really excited about what he’s done, what we hope he can keep doing.”

Elsewhere on the injury report, rookie defensive tackle Alfred Collins is listed as questionable with a knee injury he suffered against the Rams. Collins didn’t practice Wednesday but was involved Thursday and Friday. Cornerback Upton Stout, safety Malik Mustapha and defensive tackle Kalia Davis are also questionable.

Defensive tackle Kevin Givens (pectoral) and lineman Yetur Gross-Matos (hamstring) have also been ruled out.