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 49ers and their growing concerns along the offensive line.

The NFC West has emerged as the weakest division in football. The Rams are atrocious, the Cardinals are in transition mode and nobody quite knows what to make of the new-look Seahawks.

That’s why the 49ers are so intriguing. People have fallen in love with Mike Singletary’s coaching style and are encouraged about the development of former No. 1 overall pick Alex Smith. They also have a great talent at running back in Frank Gore, a suddenly decent receiving corps thanks to Michael Crabtree, a stud tight end in Vernon Davis, and a young, energetic defense that has taken on Singletary’s ferocity and swagger.

But Smith and the rest of the offense will only go as far as the offensive line takes them and as of this moment, things don’t look good for the Niners’ front five.

Singletary has already named rookies Anthony Davis and Mike Iupati the starters at right tackle and left guard, respectively. Both first-rounders certainly have the talent to succeed, but as with any young player in the NFL, Davis and Iupati will likely struggle in their first years. It’s only inevitable.

That’s why it’s important for teams to have a good supporting cast when starting rookies, which is something the Niners don’t have at the moment. Center Eric Heitmann broke his left fibula during a recent practice and will be out six to eight weeks. That’s a crushing blow considering Heitmann hasn’t missed a start since breaking his leg in 2006 and was arguably the team’s best linemen last season.

Heitmann’s injury creates a domino effect along the team’s offensive line, as former left guard David Baas now moves to center, which is a position he is highly unfamiliar with. Seeing as how the center calls the audibles, sets the line and snaps the ball, Baas’s inexperience at the position is a major concern. (Don’t forget that offensive coordinator Jimmy Raye also likes to use Smith out of the shotgun, putting even more importance on the snap.)

Adam Snyder will slide over from right tackle to right guard this season after turning in a train wreck of a 2009. He was easily the weak link on a line that had trouble gelling a year ago and if he can’t make the transition from tackle to guard, then he won’t be long for the 49ers or the NFL.

At left tackle is Joe Staley, who is highly considered the team’s best offensive linemen. But he played in just five games last year due to injuries and has trouble staying on the field on a whole. He’s a big, powerful blocker and more than capable of protecting Smith’s blindside, but he needs to stay on the field if the Niners are going to have success this season.

Now, can San Fran’s offensive line turn into a strength at some point this year? Absolutely, especially considering it’s comprised mostly of former first round picks. Plus, once Heitmann returns from injury, Baas can either provide depth or take over for Iupati or Snyder if they struggle.

But again, having two rookies start on the offensive line usually spells trouble. Plus, ask the Packers how shuffling players from one position to another worked out for them last season.

Davis and Iupati could be excellent players at some point during their careers and the 49ers did a great job of recognizing their biggest weakness and addressing it during the offseason. But as of right now, the team has more questions than answers along the O-line.