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The San Francisco 49ers have many needs going into the offseason, though most are on the offensive side of the ball.

They'll undoubtedly look to fill some of those voids in the 2015 NFL draft.

When looking at a team's needs, I'm focused most on the quality of the starters from each unit. For example, if a team has decent starters and average depth at one position and awesome starters and no depth at another, I'm assuming it'll look to improve the decent starters before acquiring depth at the other position.

The 49ers are set at safety and linebacker for quality and depth. They'll be strong at defensive line if Justin Smith returns for one more season. Though they could use more depth at D-line behind Ray McDonald, Tank Carradine, Ian Williams and Glenn Dorsey, they have bigger needs at other positions.

On offense, tackle is the position with the most clarity. Joe Staley is set at left tackle, and Anthony Davis is under contract through 2019. Another talented running back would be useful, but Carlos Hyde and Kendall Hunter should be just fine splitting the role if Frank Gore retires or signs elsewhere.

The following positions are in most need of an upgrade through the draft.

Wide Receiver

What do Michael Crabtree, Anquan Boldin and Stevie Johnson have in common?

None can take the top off a defense.

The lack of speed from San Francisco's wide receivers is making life difficult on Colin Kaepernick (who, admittedly, isn't throwing them open, either). The receivers aren't creating separation.

For several years, the 49ers have needed a speedster. They used a late-first-round pick on A.J. Jenkins in 2012 to be that guy, but he turned out to be a bust.

This draft class isn't as strong at wide receiver as the 2014 class was, but there are still plenty of speedy options from which to choose.

Alabama junior Amari Cooper is the obvious top choice, but assuming he's off the board before San Francisco picks, West Virginia senior Kevin White or Auburn junior Sammie Coates would add a speed element to the 49ers offense that's lacking.

If Crabtree signs with a new team, wide receiver becomes San Francisco's No. 1 need. However, if he re-signs with the 49ers—which seems unlikely—receiver will still be a long-term need, as Boldin, 34, has only one year left on his contract.

Cornerback

In the Harbaugh era, the 49ers have relied on lesser-known cornerbacks, most of whom were mid- to late-round draft picks made by San Francisco. For the most part, the 49ers have had success with this strategy.

They'll surely look to find another CB gem in the 2015 draft.

Tramaine Brock is under contract for three more seasons, though he's no sure bet to play a full season next season after dealing with injuries throughout 2014. Chris Culliver and Perrish Cox are scheduled to be free agents at season's end, and both are likely to be pursued by other teams in free agency.

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Jimmie Ward and Dontae Johnson are part of the long-term plan, but neither looked like a future shutdown cornerback in their rookie season.

This year, the 49ers learned the hard way they can never have enough defensive backs on the 53-man roster. They may not use a first-rounder after taking Ward last year, but they'll likely look for a player they project will be a starter down the road (so Ward can move to safety).

An option in the second round is Wake Forest's Kevin Johnson, whom Bleacher Report's Matt Miller wrote is "soaring up boards."

Tight End

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I don't know what happened to Vernon Davis. But it seems obvious his 49ers tenure is coming to a close sooner rather than later. He has one year left on his contract.

Meanwhile, 2013 second-round pick Vance McDonald has been a huge disappointment. The 49ers could use a short- and long-term upgrade at tight end.

This draft class isn't loaded with great options, so the 49ers may look to free agency for a short-term option. CBS Sports has Notre Dame senior Ben Koyack, Miami senior Clive Watford and Florida State senior Nick O'Leary as its top three TE prospects. All have the potential to start on Sundays.

Offensive Guard

Guard is only a short-term priority if Mike Iupati doesn't re-sign with the 49ers and Brandon Thomas isn't the 2014 NFL draft steal many think he is.

In case Thomas doesn't fully recover from the injury he suffered in a pre-draft workout, the 49ers would be wise to draft another guard.

Long term, San Francisco has to consider whether keeping Alex Boone is the best option at right guard.

Boone held out during training camp before agreeing to a raise over the final two years of his contract. He is scheduled to be a free agent after the 2015 season, and it would come as no surprise if he plays the market.

To recap, the 49ers may need to replace both of their starting guards by 2016, and Thomas is the only suitable option on the roster.

Guard may not be as big a need as wide receiver, cornerback or tight end, but it's a need nonetheless.

Quarterback

I doubt that the 49ers are going to give up on Kaepernick after this season. However, at the very least they should go into next season with a capable backup quarterback. In other words, they need a better option than Blaine Gabbert.

San Francisco will likely address this need in free agency. But it wouldn't be a bad idea to draft a project just in case Kaepernick completely falls apart next season.

Because if he has another bad year, the 49ers could cut him without much financial burden. Just read what Mike Florio of Pro Football Talk wrote after Kaepernick signed a six-year extension in the offseason.

As one source put it, Kaepernick can feel good about the deal because he has a lot more guaranteed money today than he had yesterday. But the same source also added that the 49ers are nevertheless “thrilled” with the contract, which allows them to control Kaepernick’s rights for seven years and to move on after any of the next six seasons, if they ultimately decide that Kaepernick is more like the guy who struggled at times during the 2013 regular season and less like the guy who found the gas pedal in the playoffs.

Kaepernick can shush all of his critics (at least temporarily) by beating the Seahawks in Seattle next week. But if he finishes this season as poorly as he's played the last two games, the 49ers will have to consider a contingency plan at quarterback.

Taking a flier on Baylor senior Bryce Petty or Colorado State senior Garrett Grayson could pay off in a big way down the road.