SANTA CLARA – Deebo Samuel avoided a catastrophic season-ending injury and could be back before the 49ers’ regular season ends in four weeks.

Brock Purdy also clearly avoided a significant setback after winning his starting debut Sunday and is listed as “day-to-day” with left oblique and rib injuries.

That should mean Purdy is a try for the 49ers (9-4) on Thursday night when they can clinch the NFC West with a win over the Seattle Seahawks (7-6). If he can’t play, backup Josh Johnson will start in his place after being left off the Denver Broncos’ practice squad last week.

Samuel may need more recovery, but he is “expected to return at some point during the regular season,” the team announced as it revealed his MRI results Monday confirmed left knee and ankle sprains, with no fractures.

It certainly painted a better picture than the one that unfolded after a second-quarter run in Sunday’s 35-7 home win over Tampa Bay. After emotionally burying his head in his hands as he was wheeled to the locker room, Samuel responded to Monday’s news by tweeting: “That Ain’t Nobody But GOD.”

A more serious update came for veteran defensive back Dontae Johnson, who was diagnosed with a season-ending ACL tear, an injury sustained while covering the second-half kickoff.

Purdy’s victorious first start did not come without pain..

“It was a challenge for him, just talking to him and seeing him after the game,” coach Kyle Shanahan said at a media conference before Monday’s MRI results. “He toughed it out and did good things with it. I know he’s sore today.”

A win in Seattle would do more than clinch the division: It would also secure the 49ers at least the NFC’s No. 3 seed ahead of the NFC South winner. The Eagles (12-1) and Vikings (10-3) are ahead of the 49ers on the playoff ladder, and the 49ers’ conference record (7-2) could help in a possible tiebreaker with the Vikings (6-3).

Purdy’s injury is not as serious as those that sidelined his predecessors, Trey Lance (Week 2 ankle fracture) and Garoppolo (Week 13 foot fracture).

Purdy was hurt, Shanahan believes, on the 49ers’ second series, scrambling to the right and ducking a yard short of a third-and-11 conversion; a holding penalty by Trent Williams negated the game.

“Then it got worse for him throughout the game,” Shanahan said of Purdy’s oblique problem.

Purdy showed no signs of hindrance, though his left side endured a big hit from Akiem Hicks after Purdy dropped a 32-yard touchdown pass to Brandon Aiyuk for a 28-0 lead just before halftime.

Purdy produced touchdowns on four of the next five possessions after the second-down scramble. He was eventually pulled for Josh Johnson through the fourth quarter. Behind Johnson, the 49ers’ only other internal quarterback who is healthy is Jacob Eason, on the practice squad.

Johnson, 36, played the final two drives Sunday and was 1-of-2 passing. Since breaking into the NFL in 2008 with the Bucs, Johnson has had stints with 14 franchises, including with the 49ers in 2012, ’14, ’20 and this season. He is 1-8 all-time as a starter.

Johnson’s vast experience and familiarity with Shanahan’s offense contributed to his arrival last week.

None of the previous 56 Super Bowl winners have reached the postseason with four different starting quarterbacks. The 49ers’ goal is to become the eighth team to stick with three different starters.

After Sunday’s game, Shanahan took a seat next to Purdy at his locker. The sixth-year coach checked on Purdy’s health, they discussed the game, last week’s preparation and how this week’s work will unfold.

“He brought up a couple of plays he missed in practice during the week that killed him, said he knew he’d get them down by game day, which is amazing because he had a great week of practice,” Shanahan said, noting. that Purdy also said he had a lot of fun in the game. “It just shows you that the kid is a perfectionist and everything he does, he wants to see what he can do better.”

One play Purdy likely wanted back was his first: On the opening snap, he called a man-coverage call that left safety Keanu Neal unblocked. Neal sacked Purdy, only he did so by leading with his helmet and drawing a roughing-the-passer penalty.

“He regretted it (audible) pretty quickly, but he came back from the hit pretty quickly,” Shanahan said Monday. “Sometimes these plays wake you up pretty quickly.”

KINLAW A WEEK AWAY?

The 49ers lost defensive linemen Kevin Givens (knee) and Kerry Hyder Jr. (ankle) due to injuries Sunday, and don’t expect Javon Kinlaw to come off injured reserve this week to bolster that unit. The 49ers plan to open Kinlaw’s three-week practice window next week, Shanahan said. Kinlaw played in the first three games and has been sidelined since then due to knee problems that required surgery last season.

MORE ABOUT INJURIES

DT Given: He suffered an MCL sprain in his left knee just three snaps into the defense’s first series. Givens made his 11th start and has been an unheralded help to the 49ers’ run defense, while top 2020 pick Javon Kinlaw remains on injured reserve with a knee problem.

CB Womack III: Shanahan ruled the rookie out of Thursday night’s game because there isn’t enough time for Womack to clear the NFL’s concussion protocol. All 12 of his snaps Sunday came on special teams, where he has thrived this season.