What are the Lions' top needs on offense?

The 2015 offseason is an especially important one for the Detroit Lions. I suppose you could really say the same thing about every offseason, but given who is headed for free agency, the Lions have a lot of important decisions to make in the coming months. They could also have a lot of holes to fill depending on what happens in free agency.

In order to understand what needs exist, I put together a depth chart for the Lions that is based on their current roster. It includes everybody who is currently under contract, even the players who are set to become free agents in March. It also includes everybody who finished the 2014 season on injured reserve. In other words, it's meant to be an overview of what the depth chart would look like at this very moment if there were no injuries or anything like that.

First, we're going to take a look at the offense. Specifically, let's start by examining the players in the Lions' backfield:

(Note: Players highlighted in yellow are set to become free agents in March.)

Matthew Stafford is the only Lions quarterback currently under contract, but that isn't necessarily a big deal given who is behind him on the depth chart. The Lions should use this as an opportunity to make an upgrade at the backup spot. There may not be a ton of great options out there, but I have to think that they can do better than Dan Orlovsky. Even Kellen Moore seems like a better option, and he should be back since he is a restricted free agent.

At running back, everything from 2014 is still in place for 2015. That could change if the Lions decide to part ways with Reggie Bush to save some cap space, though. Then you would have a situation where Theo Riddick suddenly has an opportunity for more playing time, and the Lions could potentially add even more help by drafting a running back.

At fullback, the Lions' starter from last year, Jed Collins, is set to become a free agent. There's no reason to think he won't be back, though. Chances are he will be quite affordable, and Collins did a fine job in his role last season.

Much like running back, there isn't a whole lot set to change on paper at wide receiver and tight end. Jeremy Ross is an exclusive-rights free agent, meaning he will for sure be back if the Lions want to re-sign him, and Kellen Davis was just an injury replacement. If everybody is healthy, there aren't any real spots to fill. Tight end seems completely set, and although the Lions would benefit from making an upgrade at the No. 3 receiver spot (and at returner), that doesn't exactly seem like a top priority at this point.

Offensive line is where the needs really start to jump out, but there are some certainties with this group. The starters at left tackle and right guard are pretty much set in stone, for example, and although the Lions have already made it known that Dominic Raiola isn't coming back, that simply means that Travis Swanson will slide up to first string on the depth chart.

What isn't quite so certain is what's going to happen at left guard and right tackle. Rob Sims is set to become a free agent, and the Lions don't seem to have a capable replacement for him on their roster right now. They could simply re-sign Sims and roll with him for another year, but that seems like a spot that the Lions should focus on upgrading this offseason.

Another spot that could be subject to an upgrade is right tackle. The Lions have two young guys with starting experience in LaAdrian Waddle and Cornelius Lucas, and Waddle has been a decent starter when he's been on the field the last two seasons. The problem is that Waddle's health has been a big issue. The Lions really haven't been able to rely on anyone at the right tackle spot in recent years given the injury problems. They could simply re-sign Corey Hilliard if he is now healthy after suffering a season-ending injury, and they could decide to bet on the trio of Waddle, Lucas and Hilliard in 2015. Then again, given how that trio fared in 2014, it might be a better idea to add some extra help here via free agency or the draft.

In any case, it's clear that the Lions have some holes to fill on the offensive line. Not only do they need to address the starting spot at left guard, but they need to add some depth for the interior of the offensive line with Swanson moving into a starting spot. They also need to address the right tackle spot after it was ravaged by injuries last season.

Recap

Considering how much the offense struggled last season, you might think there are several big needs on this side of the ball. In reality, though, that's not the case. The Lions could always use a bit more depth at the skill positions, but the only major needs are on the offensive line. If they can simply shore up the O-line and get some guys healthy, the offense should be poised to take a major step forward in Joe Lombardi's second season as coordinator.