It is a slow time of year for the Detroit Lions. The franchise did not make a bunch of free-agency moves and the NFL draft is still a month away. Yet there is still one obvious, glaring hole with the Lions.

They are missing a starting offensive lineman.

Those questions and more about Detroit's offensive line populate this edition of the mailbag. On Sunday, we'll tackle a bunch of other topics. As always, to ask a question, use the hashtag #LionsMailbag on Twitter, email michael.rothstein@espn.com or pop on to the Facebook page here. Now, on to your questions.

@mikerothstein Most likely target for OG - vet like Sims or draft? #LionsMailbag

— Justin Ochsner (@jochsner4) March 25, 2015

@mikerothstein: In a word, both. The Lions are likely to bring in some veteran presence at left guard, be it the return of Rob Sims or signing another vet such as Justin Blalock. Those seem to be the two most likely options at this point. Both players are 31 years old and are no more than short-term solutions for a potential long-term problem there. Drafting a guard somewhere in the first three rounds of the draft is pretty likely. The Lions are likely looking at the Sims/Blalock and Rashean Mathis roles in the same way: Have a vet to play in 2015 (and maybe 2016) and at the same time groom a younger player to eventually replace that person. It is a good argument for bringing back Sims, actually, because the Lions understand his personality is one where he would be willing to do that.

@mikerothstein With the exception of Swanson at Center, what are the most likely changes to the OL for the 2015 season? #LionsMailBag

— Big Biting Pig (@BigBitingPig) March 25, 2015

@mikerothstein: At this point, a lot appears to be up in the air. Travis Swanson at center and Larry Warford at right guard are the only two certainties -- barring injury -- at this point. Riley Reiff will occupy one of the tackle spots on the line. It's just a matter of whether the Lions believe he is better suited on the left or right side. The left guard question is answered, for now, above. Right tackle is the interesting spot because LaAdrian Waddle is still recovering from his knee injury and Cornelius Lucas was OK, but not great, as an undrafted rookie last season. Both of those guys are in the mix, should be on the roster and don't be surprised if one starts. A wild card in here, besides the drafting of a tackle, could be Michael Williams. Having added the weight and after essentially a redshirt year on the practice squad in 2014 as he transitioned from tight end, he could make a push for the third or fourth tackle position. It would seem unlikely he'd win a starting job this year, but remember, both Waddle and Lucas began their rookie seasons as the fourth tackle and ended up starting games.

@mikerothstein Why the momentum to replace Reiff at LT? Seems pretty good. Are Waddle/Lucas/ a Rookie REALLY better? Skeptical #LionsMailbag

— Tacowrecker (@tacowrecker) March 27, 2015

@mikerothstein: It's gaining momentum because both Martin Mayhew and Jim Caldwell left open the possibility of Reiff making a move during the past two months. I was the one who asked Mayhew about it pretty point-blank at the combine because these questions have persisted for months. I'm not sure if any of those options are better than Reiff at left tackle, but Lucas seems to be a natural left tackle, so it might be worth at least seeing what he can do there during offseason workouts. The biggest potential for a move would be if the Lions drafted a tackle in the first round. That would be the bigger sign, to me, that Reiff is making the move.