SANTA CLARA, Calif. -- The San Francisco 49ers need help at cornerback.

That's not a secret to anyone who watched them give up 235.3 passing yards per game (22nd in the NFL), 6.92 yards per pass attempt (24th) and an opposing passer rating of 93.9 (24th) in 2017.

So it should be no surprise that as mock drafts populate the Internet between now and late April, the Niners are often connected to some of the best cornerback prospects available. Whether it's Ohio State's Denzel Ward or Iowa's Josh Jackson, the 49ers have become a common landing spot for top corners.

There's even been a consensus between ESPN draft analysts Mel Kiper Jr. and Todd McShay, sending Ward to San Francisco. Here in mid-February, Ward to the Niners makes plenty of sense on paper. Aside from Alabama's Minkah Fitzpatrick (who some believe is better suited to play safety), Ward is widely regarded as the best cornerback in the draft.

Adding Ward as the tag-team partner to second-year corner Ahkello Witherspoon would give the 49ers a talented young duo to build around in the secondary for years to come. If the Niners grow to believe Ward (or Jackson or some other first-round corner) is the best player available when they draft, there's nothing wrong with making that pick.

But here's the thing: Long before the 49ers should even be in position to draft a cornerback, they should have already addressed their need at cornerback in a meaningful way. Free agency always changes the look of mock drafts as teams fill needs. The 49ers don't have a long track record under new general manager John Lynch, but his philosophy is to to fill needs in free agency and free the Niners up to take the best players available early in the draft.

In the Niners' case, there are multiple reasons why they should prioritize cornerbacks in free agency rather than waiting until the draft to address that particular need. Let us count the ways:

1. The 49ers could use a veteran presence at cornerback: The full-blown youth movement that took place in San Francisco was meaningful in that many young players got valuable repetitions. The Niners also employed a solid veteran at just about every position on the roster. That's helpful for the young talent in those position rooms when they need someone to lean on. With Dontae Johnson headed toward free agency and unlikely to return, the Niners' most experienced corner is nickel K'Waun Williams, who has all of three healthy NFL seasons under his belt.

More importantly, the Niners now look like a team with legitimate postseason aspirations after the acquisition and retention of quarterback Jimmy Garoppolo. That's not to say there's a desperate need to win now but the window is starting to open. Adding a proven commodity at cornerback would help solidify one of the team's most glaring weaknesses.

2. There should be good cornerbacks available in free agency: For the most part, teams don't let their best players hit free agency, but simply because of the nature of the cornerback position -- meaning teams essentially need three starters these days -- it often leads to some talented ones hitting the market. Put simply, teams often can't afford to pay for more than one top cornerback. On the flip side, there are certain positions where teams don't let top players get away.

Let's use edge-rusher as an example. The 49ers have a pressing need there that rivals what they have at cornerback. This year's top edge-rusher who could hit the market is Dallas' DeMarcus Lawrence. The Cowboys are all but certain to tag him. Look back at other players who were tagged or re-signed to big deals in recent years and you would struggle to find legitimate outside pass-rushers who got away. Last year, the Chargers tagged then signed Melvin Ingram; Arizona did the same with Chandler Jones and the Giants followed suit with Jason Pierre-Paul.

Meanwhile, it's become fairly common for highly sought cornerbacks to be available. In 2017, Jacksonville shelled out big money for A.J. Bouye, New England paid Stephon Gilmore and Tennessee handed Logan Ryan a lucrative deal.

This year, there should be a handful of talented corners available, pending the use of tags. The Rams' Trumaine Johnson, Chicago's Kyle Fuller, New England's Malcolm Butler and Indianapolis' Rashaan Melvin are among the talented and intriguing names poised to hit the market. It's a safe bet at least a couple, if not all of them, will be free to test the market. That doesn't even account for potential cap casualties such as Denver's Aqib Talib. And the Niners have already hosted veteran Vontae Davis on a free-agent visit.

Projected to have the third-most cap space in the league entering free agency, the 49ers have the resources to bid on any corner they believe is a good fit in their Cover 3 defense.

3. Positional scarcity carries over to the draft: This is a little more difficult to quantify because the depth of talent at a position in the NFL draft is in the eye of the beholder. Still, positional scarcity and emphasis isn't limited to free agency. Just like teams won't allow top edge-rushers to test free agency, they put a higher value on those players in the draft.

The early read on this year's draft is that there's not a lot of top edge-rushers available and if you want one, you'd better select one fairly early. Meanwhile, the cornerback class is already being hailed as one of the draft's strengths. Just last year, the Niners grabbed Witherspoon in the third round and he's already emerged as a starter they believe in moving forward.

Given their need at the position, the Niners would still be wise to draft a corner even if they land a veteran in free agency. They could do it in the middle rounds and still land someone capable of contributing. But unless Ward, Jackson or someone else emerges as the clear-cut best player on the team's board when they draft in the first round, the Niners would be better off using their most valuable draft capital elsewhere.