SANTA CLARA — Colin Kaepernick has lost 13 of his last 16 starts, and none looked worse in that span or even his entire 49ers career than last season’s visit to Arizona.

Sunday’s return trip to the desert offers Kaepernick a potential turning point for him and the 49ers.

“It’s a good opportunity to go back, redeem myself and try to help get this team back on track,” Kaepernick said Tuesday.

The 49ers (1-7) have lost seven straight, and in the process, they’ve given Kaepernick a second chance at reviving his career, one arguably known more nowadays for his national-anthem protest and racial-equality movement than his on-field efforts.

Other than mentioning he abstained from voting Tuesday, Kaepernick’s media session focused on football, including last Sunday’s 398-yard passing effort against the New Orleans Saints and the upcoming matchup with the Cardinals (3-4-1),

The dark cloud hovering that discussion, however, was last seasons’ 47-7 rout at Arizona. Two of his first four passes were so telegraphed they easily got intercepted and returned for Cardinals touchdowns, putting the 49ers in a 14-0 hole.

“Yeah, it probably was the worst game of my career,” Kaepernick said.

Cardinals defensive back Tyrann Mathieu, who scored the second pick-6, offered a startling assessment after the game: “Their passing game has just simplified so much, it was easy for us to anticipate routes, get some good breaks on the ball today.”

Kaepernick’s final passing line: 9 of 19, 67 yards, career-high four interceptions, career-low 16.7 passer rating.

Kaepernick said he hasn’t dwelled on that game, and one of his closest teammates, safety Eric Reid, said last season’s fiasco could actually help Kaepernick’s mindset Sunday.

“He’s been through it all,” Reid said. “He came into this league as a backup, rose to the top, to the highest of highs in this league, and then he had a low point. And now he’s battling back from that.

“That’s helped him,” Reid added. “There’s not too much he hasn’t seen, too many emotions he hasn’t felt. It will play well for him in the long run.”

Kaepernick played his best game of the season Sunday, albeit in a 41-23 loss to the Saints. He downplayed the second-highest passing output of his career by acknowledging the 49ers must score more points. They lost 45-16 at Buffalo and 34-17 against Tampa Bay in his previous starts since repossessing his starting job from Blaine Gabbert.

Offensive coordinator Curtis Modkins said Tuesday he wants to see better accuracy in the pocket from Kaepernick. Modkins wasn’t about to question Kaepernick’s mental strength, however, in terms of returning to Arizona.

“Colin is a strong young man,” Modkins said, “and I don’t think he’s going to let anything that happened in the past shackle him for what he does in the future.”

— Arik Armstead’s second season is done after he aggravated a season-long shoulder injury Sunday. The 2015 first-round draft pick went on injured reserve Tuesday afternoon.

When training camp opened, Armstead looked poised for a breakout season in his first full-time role. But a week into camp, he hurt his left shoulder, and although he played through the injury for eight games, he aggravated the injury on Sunday’s first series while reaching for a ball-carrier. The 6-foot-7 defensive tackle started the past four games and he finished the season with 21 tackles, 2 1/2 sacks and a forced fumble. DeForest Buckner, Glenn Dorsey and Quinton Dial figure to start on the defensive line Sunday.

— Armstead’s roster spot went to another defensive tackle, Chris Jones, who got claimed off waivers from the Miami Dolphins. Jones (6-1, 293 pounds) played the previous three seasons with the New England Patriots and the first seven games this season with the Miami Dolphins, who released him Monday.

— Cornerback Will Redmond, a third-round draft pick, won’t play at all his rookie season and will revert to injured reserve. The 49ers envisioned Redmond as their only player eligible to come off injured reserve, but his three-week practice window closed Tuesday with his reconstructed knee not ready to proceed onto the 53-man roster, general manager Trent Baalke told this newspaper.

Redmond tore an anterior cruciate ligament last October at Mississippi State, but that did not deter Baalke from making him to the seventh ACL-recovering player drafted without much, if any, success since 2013. “Very comfortable with where he’s at and very comfortable that he’ll be ready to go come training camp,” Baalke said upon drafting Redmond in April.

Although Redmond won’t be bailing out the league’s last-ranked defense, Baalke noted the 49ers may have found a gem in JaCorey Shepherd, who was acquired Oct. 10 and has shown promise as a nickel back. Shepherd made a positive impact as a kickoff returner Sunday.

— Defensive coordinator Jim O’Neil insisted his unit is showing signs of improvement, even though it is on track to allow the second-most points and yards in NFL history. “There have been three different coordinators here in three years. I came here to help with the problem or be part of the new staff,” O’Neil said. “I believe in what we’re doing and in Coach (Chip) Kelly. Consistency wins in this league.”

— Wide receiver Torrey Smith (back) did not practice. He has not missed a game in his six-year career.

— Running back Carlos Hyde, who’s missed two games since spraining his shoulder Oct. 16, practiced in a non-contact jersey.

— Outside linebacker Aaron Lynch (ankle) and cornerback Rashard Robinson (knee) did individual conditioning on a side field.

— Wide receiver Chris Harper, rather than 2015 draft pick DeAndre Smelter, got promoted from the practice squad, and Mose Frazier was signed to fill Harper’s spot. The 49ers made room for Harper (No. 14) by releasing Keshawn Martin, who was inactive the past two games since fumbling a kickoff return at Buffalo.