Over the next two weeks, we will take a position-by-position look at where the Vikings stand heading into the offseason after their 7-9 season in 2014. Today, we conclude this series with special teams.

Highlighted by the big plays of rookie kickoff returner Cordarrelle Patterson, the Vikings had one of the NFL's most explosive special-teams units in 2013. Patterson averaged a league-high 32.4 yards per kickoff return as he took a pair of kickoffs to the house. Marcus Sherels ranked second in the league on punt returns with a 15.2-yard average, and he scored on one of those, too. Kicker Blair Walsh backed up his strong rookie season with another steady season.

In 2014, Patterson and the Vikings lacked touchdowns in the return game (they did score twice on blocked punts while beating the Panthers) and Walsh was uncharacteristically inconsistent. But the Vikings were much better covering kicks and punts, which played a large part in the team actually improving in the most notable (make that the only notable) special-teams rankings around.

Rick Gosselin of the Dallas Morning News reviews all facets of special teams when compiling his annual cumulative rankings of special-teams units, and according to his calculations, the Vikings rose from 17th in the league in 2013 to tenth this past season.

Still, despite the improvements the Vikings made in some areas, the special teams were far from perfect in 2014.

ONE REASON FOR OPTIMISM: In 2013, only seven teams allowed more kickoff return yards than the Vikings. Only the Broncos allowed a higher average on kickoff returns. And the coverage teams allowed both a kickoff and a punt to be returned for touchdowns. Things were much different in 2014. Thanks in large part to Walsh's booming leg on kickoffs, the Vikings allowed just 579 yards on kickoff returns — which was roughly half as many as in 2013. While punter Jeff Locke's punts sometimes left more to be desired, the Vikings only allowed 6.5 yards on punt returns. That is significant improvement from the coverage teams.

ONE REASON FOR CONCERN: Walsh was one of the NFL's most accurate kickers in his first two seasons, missing just seven total field-goal attempts over that span. This past season, though, Walsh missed nine and his 74.3 accuracy percentage was dead last among qualifying kickers. Four of Walsh's misses were from beyond 50 yards. But five came within 50 yards and three were within 40, which is alarming. Can Walsh bounce back in 2015?

GRADES WITH A GRAIN OF SALT: Since the Vikings (understandably) won't make their player grades public, we turn to Pro Football Focus, whom some players and coaches have been critical of. For context with these grades, a grade of 0.0 is considered average. Positive grades are good. Negative grades are not. Despite his struggles trying to kick the ball between the uprights, Walsh, due to his touchback total, led the way with a plus-8.2. Adam Thielen was a plus-7.8. Everson Griffen, Jabari Price, Audie Cole and Patterson were also in the green. Long snapper Cullen Loeffler had the lowest grade at negative-18.5 due to what PFF felt were errant snaps. Locke was a negative-10.7. And Shaun Prater, Matt Kalil, Sherels, Antone Exum and Gerald Hodges were also in the red.

STAT THAT STANDS OUT: 38.7 — net punting average for Locke, 21st among NFL punters.

POTENTIAL DEPARTURES: Loeffler is a free agent. It wouldn't cost much to bring him back, but the Vikings must decide whether they want to stick with him for another season or go young there. Joe Berger, Matt Asiata, Jerome Felton and Corey Wootton are free agents who had roles on special teams, but none of them were core special-teamers.

OFFSEASON LEVEL OF NEED: Moderate. There is constant turnover on the special-teams unit — that's how it goes in the NFL — but special teams coordinator Mike Priefer and the Vikings groomed a bunch of rookies and young players to help out in that phase this past season. Their return games could use a boost, but that won't require anything drastic. And then there are the specialists. They may replace Loeffler. And while Locke, who struggled in the first half of the season but was better down the stretch, is still under contract, the Vikings should consider bringing in someone, whether it is a veteran or an undrafted free agent, to push him during offseason workouts and training camp. Then let the best man win.