PHOENIX -- The San Francisco 49ers moved quickly to address what they believed were their two biggest needs in the opening days of free agency: stack linebacker and edge rusher.

To that end, the Niners signed linebacker Kwon Alexander and traded for defensive end Dee Ford. Conspicuous in its absence from those points of emphasis was a secondary that finished the season as one of San Francisco's biggest question marks.

In 2018, San Francisco's defensive backfield amounted to a big game of musical chairs, with the exception of Richard Sherman at left cornerback. A whopping 12 players started at least one game at the four primary positions in the secondary plus nickelback. Of those, eight started five or more games and only Sherman started more than 12 games with 14. Cornerbacks Ahkello Witherspoon and K'Waun Williams were the only other defensive backs on the roster to start at least 10 games.

Yet, in a market brimming with talented safeties and, to a much lesser extent, intriguing cornerbacks, the 49ers mostly stood pat. They re-signed safety Jimmie Ward in hopes that his five-year history of injury issues will be a thing of the past, and took a flier on cornerback Jason Verrett, who has played in just five games over the past three seasons and is coming off a torn Achilles.

And so, barring a trade or a late veteran signing, the 49ers will go into the 2019 season with a secondary that, outside of Sherman, will consist largely of the same unproven products that struggled last season.

"You can’t go pay everybody out there," coach Kyle Shanahan said. "We went a different direction at those positions. We also know how good of a player Jimmie is. There is always a risk with his injury history. The injuries he’s had the two years we’ve been here I think have been pretty freak accidents, breaking his wrist and things like that. So, we got a good player. Hopefully he’ll be able to stay healthy and we’ll be able to add at other positions by avoiding that area."

Of course, the 49ers could and likely still will add in the secondary via the draft, but even a sizable investment there guarantees nothing in terms of proven value. Instead, the Niners will roll the dice that the likes of strong safeties Jaquiski Tartt and Marcell Harris, free safeties Adrian Colbert and Ward and cornerbacks Witherspoon and Tarvarius Moore can not only stay healthy but make meaningful strides in their development.

In 2018, the aforementioned lack of continuity contributed greatly to a lack of production. For the season, the Niners managed just two interceptions, worst in the league, and gave up 35 passing touchdowns and a 105.4 passer rating, both of which ranked 31st in the league.

Given that, it's fair to wonder why the 49ers are comfortable going into next season with so few proven commodities. To that question, there are two answers.

"I feel this is the first year we can have some legit competition at all positions," Shanahan said. "Whoever wins the starting job, that’ll make us better on defense and it’ll also make us better on special teams."

Indeed, while Sherman is clearly the player with the strongest track record (and the Niners and Sherman are looking forward to having him closer to 100 percent now that he's more than a full year removed from a torn Achilles), the 49ers won't be lacking for bodies.

Sherman's spot is the only lock and Williams is likely to remain at nickel, but the competition should run through the offseason program and the preseason. And that doesn't include any potential draftees.

Getting the healthy version of Verrett could be the biggest boon to the secondary if he can rediscover previous form. Although the sample is small, he's the only corner other than Sherman who has played at a Pro Bowl level in the NFL. Verrett signed a one-year deal worth up to $3 million in San Francisco knowing there was a chance to win a starting job and re-establish himself.

"I played in the league, I’ve made plays in the league and I’ve dealt with big receivers, small receivers, if you can ball, you can ball," Verrett said. "I know I’m definitely a top corner in this league when I’m healthy. I’ve just got to prove it. The 49ers are giving me the opportunity to do that and that’s my plan."

On paper, the 49ers should be able to find capable starters and there are reasons to believe that it can be better in 2019. Despite the lack of turnovers and the amount of touchdowns allowed, San Francisco finished 10th in completion percentage allowed (63.5), 11th in passing yards allowed (3,752) and 12 in yards allowed per attempt (7.3).

One other way the Niners believe their secondary will improve in 2019? With the help of a super-charged pass rush that has already added Ford and is quite likely to add another top talent in the early parts of the draft.

"I think it’s huge," Shanahan said. "The better your pass rush is, that hides a lot of problem. We’ve been pretty stacked with some inside pass rush, adding an outside pass rush has been of huge importance to us, and it started with getting Dee."

No matter the method, if the Niners are to make a jump to contender status in 2019, they'll need some familiar faces to take a big step forward.