Merry training camp season, everyone. It’s been a long offseason, but football is finally gearing up again and to celebrate I’m rolling out a new series on TSR entitled “2010 NFL Question Marks,” where I discuss one or two of the biggest concerns that teams have heading into the new season. Granted, some teams have more issues than others, but I’ll primarily be focusing on the biggest problem areas. Today I’ll be discussing the Vikings’ secondary concerns.

There’s growing sentiment that the offensive line is the Vikings’ biggest question mark heading into the 2010 season and for good reason. Neither Steve Hutchinson nor Bryant McKinnie played well last year and some pundits believe that Phil Loadholt looks the part, but has a long way to go to be consistently productive.

But keep in mind that Hutchinson has dealt with back issues for the last couple of years and also had a shoulder injury that limited him last season. McKinnie had his own injury concerns (he played with plantar fasciitis for most of the year) and that was only Loadholt’s first year. Considering the Vikings added two new starters to the O-line, it makes sense that they struggled a bit – especially in run blocking.

Hutchinson and McKinnie are reportedly healthy and if both Loadholt and center John Sullivan make strides in their development, the offensive line should be fine. Their secondary on the other hand…

It seems like the Vikings have had the same issues in their secondary for about a decade now. Even in 1998 when they went 15-1 and lost in the NFC Championship Game their biggest weakness was arguably their secondary and despite their best efforts over the years, they can never seem to get the right mix of players back there.

Cornerback Antoine Winfield remains the team’s most vital piece in the defensive backfield, but a broken foot hampered him during the second half of 2009. He says the foot is fully recovered and the Vikings better hope it is, because they lack depth behind him.

On the other side, there’s no timetable for Cedric Griffin’s return from a torn ACL. It stands to reason that it’s going to be a while before he returns to the field and that means Lito Sheppard or impressive rookie Chris Cook will start on the right side.

Sheppard is injury prone himself and is highly inconsistent in coverage. His skills have been declining for some time now, which is why Cook is getting a long look as the starter. A physical and athletic player out of Virginia, Cook could be the upgrade that the Vikings’ secondary has been longing for.

But while cornerback is less of a problem now than at the start of training camp, the safety position still remains a huge issue.

Tyrell Johnson and Jamarca Sanford are currently battling it out to see who will start Week 1 at strong safety. Both players are effective against the run, but struggle in deep coverage (which, truth be told, can describe most strong safeties in the league). The Vikings would love it if Johnson (a former second round pick) won the job, but he struggled with missed tackles last season and was also slowed by a concussion.

At free safety is the veteran Madieu Williams, who is solid in coverage but can’t seem to stay healthy. He’s a true centerfielder in every sense of the word, but nagging injuries always crop up to derail his season.

Of course, no matter who starts in the secondary, the entire unit will be helped by the outstanding pass-rush that the Vikings’ front four generates. The team’s woes in the secondary are usually masked by the effectiveness of the defensive line and assuming Jared Allen and company are at the top of their game, they will be again this year.

But while the Vikings are an obvious playoff contender, this isn’t a team that can sustain one or two injuries on defense and have it not cause a domino effect throughout the rest of the unit. Like all teams, Minnesota has to stay healthy.