SANTA CLARA Alfred Morris Jersey White , Calif. (AP) — Opportunity is slipping through San Francisco’s young defensive backs’ hands.Through 12 games, the 49ers have just two interceptions — the fewest in the NFL — and it isn’t always for lack of being in position to make big plays. Their pass defenders simply can’t secure the football when it does come their way.“Every game it seems like the ball’s on the ground or we’re missing an opportunity,” 49ers defensive coordinator Robert Saleh said. “They are going to come in bunches, but it’s baffling to me that we haven’t been able to get (more interceptions).”Losing the turnover battle goes a long way toward explaining the 49ers’ 2-10 record as they prepare to host the Denver Broncos on Sunday.San Francisco’s minus-20 turnover margin is the worst in the league. The 49ers have turned the ball over 25 times but generated just five takeaways themselves.Part of that, at least in terms of pass defense, can fairly be attributed to the youth and inexperience in the secondary.Former All-Pro cornerback Richard Sherman lends veteran wisdom in his first year with the team. But second-year cornerback Ahkello Witherspoon has been picked on by opposing quarterbacks on numerous occasions this season.Witherspoon also failed to haul in a potential interception on a slant pass that he defended well last week against Seattle.Due to injuries, the 49ers are expected to start a pair of rookies at the safety positions Sunday in D.J. Reed and Marcell Harris, who have a combined 15 games and two starts of NFL experience between them.Reed, at free safety, is replacing the injured Adrian Colbert, who is only in his second season himself.Sherman said young defensive backs often get themselves in position to make plays but lose concentration on the most important part – wrapping up the football for an interception.“The old saying was the reason they play ‘DB’ is because they can’t catch, but I don’t think that’s as true anymore,” Sherman said. “Some of it is just guys panicking. Guys getting big eyes and seeing the end zone and seeing space in front of them and not going through the last second of looking the ball in.”But Sherman, a four-time Pro Bowl player in his eighth season, hasn’t helped in this department either. He entered the season with 32 career interceptions, most among all active players since 2011, but has yet to record one in 2018.In Sherman’s defense http://www.49erslockerroom.com/authentic-k_waun-williams-jersey , he isn’t getting that many opportunities since opponents are choosing to target Witherspoon in coverage more.Never has Sherman recorded fewer than two interceptions in a season.Is he aware of that stat?“Yeah, (but) the ball will get where it gets,” he replied.Denver quarterback Case Keenum threw 10 interceptions through the Broncos’ first eight games, but he hasn’t been picked off a single time over the past four.NOTES: Receiver Marquise Goodwin practiced for the second day in a row and looks poised to return to the lineup after missing the past two games while being away from the team for personal reasons. With fellow starting receiver Pierre Garcon (knee) not having practiced Thursday, there seems a decent chance that rookie Dante Pettis draws the start opposite Goodwin against Denver. Pettis is coming off a breakout game against Seattle (5 catches, 129 yards, 2 TD’s). … Safety Antone Exum (knee), cornerback K’Waun Williams (knee) and linebacker Malcolm Smith (Achilles) were limited in Thursday’s workout.Three keys for a 49ers’ victory against the Cardinals Amidst a five-game stretch where the 49ers play the Chiefs, Chargers, Packers and Rams, the most winnable game is this Sunday against the Cardinals. Arizona comes into San Francisco winless on the season, with rookie quarterback Josh Rosen making his second start. On the other sideline, quarterback C.J. Beathard suits up as the starter for the second straight week after Jimmy Garoppolo went down for the season. Both teams are trying to find their footing after rough patches to start the season. Kyle Shanahan possesses the better roster and more experienced quarterback, so it’s time for the 49ers to go out and be the better team on Sunday. If they’re going to be successful on Sunday, here’s where San Francisco should start.1. RB Matt Breida must have a season-high in rushing attemptsWhile 49ers’ running back Matt Breida is third in rushing yards in the NFL, he’s only attempted 11, 11 K'Waun Williams Jersey White , 10, nine rushes in the 49ers’ four games. What’s awaiting Breida and the 49ers’ rushing attack on Sunday? Oh, only the third-worst rushing defense in the NFL in the Cardinals. Arizona has given up 565 yards on the ground, just slightly ahead New England and Detroit.Week 1 vs. Washington, running back Adrian Peterson rushed for 96 yards and one touchdown against Arizona. Last week, Seahawks’ running back Mike Davis rushed for 101 yards on the ground and two touchdowns, helping pave the way for a victory. So the 49ers aren’t going up against the ‘85 Bears on Sunday. Other than Rams’ Todd Gurley II, Matt Breida’s likely the most talented running back that the Cardinals’ defense will be facing up till now. The second-year running back is averaging 7.6 yards per attempt on the ground, leading the NFL in that category. If San Francisco can feed Breida the ball at least 15 times, then they’ll be able to move the ball, while keeping Rosen and the Cardinals’ offense — and the 49ers’ shaky defense — off the field. If Breida finishes the game with at least 100 rushing yards and 15 attempts, the chances of a 49ers’ victory is pretty high.2. Cardinals’ WR Larry Fitzgerald needs to have a quiet afternoonDespite various ailments, it looks like veteran wideout Larry Fitzgerald is going to suit up on Sunday, much to the disappointment of 49ers’ defenders. The Cardinals’ No. 1 receiver has absolutely torched San Francisco in years past.Last season, Fitzgerald had 12 catches for 132 yards in one game, while he hauled in six catches, 81 yards and a touchdown in the other matchup. Two seasons ago Dwight Clark Jersey , the Cardinals’ receiver had 19 catches for 200 yards and two touchdowns. Historically, Fitzgerald has been a thorn in the 49ers’ side and he has a chance to be a problem again. Rosen is known to be an accurate passer and nothing helps a young quarterback like a large target. San Francisco is likely going to be without corner Richard Sherman, leaving either Ahkello Witherspoon, Jimmie Ward or Greg Mabin on duty. The trio of corners will need to slow down Fitzgerald, otherwise it could be a long afternoon for the 49ers’ defense.3. 49ers need to get off the field on third downsWell, duh Akash. Obviously, the 49ers’ defense needs to get stops on third downs and force the Cardinals’ offense off the field, this is mostly common sense. Let’s add some numbers to it, to spice it up.Till this point in the season, Arizona’s offense has been the fourth-worst at converting third downs, only moving the chains 29 percent in a third-down situation. That’s only ahead of Dallas, Seattle and Buffalo.On the flip side, the 49ers have been middle of the pack defending on third down. Their opponents are nearly converting 43 percent of the time — a number that’s not good enough on Sunday. They’re playing an offense that’s struggling on third down and they’re going to need to get off the field when they can. San Francisco should — key word should — come away with the win on Sunday. They are the more talented team, playing at home and if they are to prove that this rebuild is on the right track, it starts Sunday.