49ers' Mac Jones throwing as signs point toward start vs. Tampa Bay; Brock Purdy out

While a recovering Brock Purdy pushed a weight sled, San Francisco 49ers backup quarterback Mac Jones dropped back on a bum knee, turned his hips with an injured oblique, and spun a pass in the direction of a receiver. Then he did it again.

Only two short practice periods were open to the media Friday. Both were long enough to see that Jones, indeed, could still throw a football. He alternated with third-string quarterback Adrian Martinez for a handful of live passing reps after he "wasn't able" to do so just a day earlier, according to head coach Kyle Shanahan. 

The closest Jones got to his throwing motion Thursday? A few soft tosses to staffers before practice. "I'm just trying to save some throws," he said after the session.

Jones (knee, oblique), who has led the 4-1 49ers to three wins across as many starts in lieu of an injured Purdy (toe), was listed as questionable ahead of a Sunday road game against the 4-1 Buccaneers. Nursing a variant of turf toe, Purdy has been officially ruled out; he has not practiced since he re-aggravated the injury in the team's only loss this season, to the Jaguars on Sept. 28. That leaves Jones in line to start, health permitting. 

In interviews this week, Shanahan and general manager John Lynch maintained that Jones should be ready by Sunday.

Asked Friday if he had made a decision of whether Jones would play, Shanahan said, "I pretty much already have but you got to put it that way, if there's any doubt at all." Lynch added Thursday via KNBR: "We feel pretty good about where he's going to be at. … I think Mac's in good shape, who will continue to work to it by Sunday. We're hopeful and believe that he's going to be in a good spot."

Martinez remains as the only fully healthy quarterback on the active roster. The Niners signed him to their practice squad on Aug. 27. He then suited up for two games as a standard elevation from the practice squad before being promoted to the 53-man roster on Oct. 2. 

Not having thrown a pass in an NFL regular-season game, Martinez has backed up Jones in each of his 49ers starts to date.

"They've both played a lot of football, a lot of NFL football," Martinez said, "so they have valuable insight. How they see the game is always interesting for me."

Briefly: Wide receiver Jauan Jennings (ankle, rib) was a limited participant Friday for a second consecutive day. He returned to practice Thursday for the first time since Sept. 26.

He is considered questionable for Sunday along with Jones, starting safety Malik Mustapha (ACL/knee), starting defensive tackle Kalia Davis (hand), rookie defensive tackle Alfred Collins (knee sprain) and rookie nickel back Upton Stout (ankle). Collins wore a big brace on his right knee Thursday and Friday. In addition to Purdy, wide receiver Ricky Pearsall (knee), rookie wideout Jordan Watkins (calf), defensive tackle Kevin Givens (pec) and defensive end Yetur Gross-Matos (knee, hamstring) were also ruled out. Defensive end/special teams player Robert Beal (ankle) was removed entirely from the final injury report.

Buccaneers notables who will not be available Sunday include starting wide receivers Mike Evans and Chris Godwin, and starting running back Bucky Irving.

This article originally published at 49ers' Mac Jones throwing as signs point toward start vs. Tampa Bay; Brock Purdy out.