One of the biggest reasons the Lions' offensive line has struggled over the last few years is because there was a revolving door at left guard. No one was able to come in and lock that spot down like Jeff Backus has done at left tackle or Dominic Raiola at center. As a result, the entire O-line has struggled because of the lack of talent and the lack of consistency at the left guard position.
Thanks to the trade that brought Rob Sims from Seattle to Detroit, that concern over the left guard position should be a thing of the past. Sims is expected to be the starter when the season opens, and barring an injury, that starting spot should be his for the conceivable future.
Just as Sims should be locked in as the starter at left guard, Stephen Peterman should be locked in as the starter at right guard. Lions coaches think very highly of Peterman, and the injury that cost him much of the 2009 season was seen as a big reason why the Lions' offense struggled so much at times. That injury created a second revolving door at the guard positions and hurt the Lions' depth on the offensive line. With Peterman set to return from that injury and retake the starting spot at right guard, another piece of the puzzle on the offensive line is in place.
As for the backups, depth isn't all that great at guard. Sure, there is Manny Ramirez, who got quite a few starts last year. But he didn't perform all that well when he did get to start, so if Sims or Peterman were to go down, the drop off would be pretty big from starter to backup. That is especially true when you consider that the only other guards on the roster are Roy Schuening and Trevor Canfield, who have been in the league for two seasons and one season, respectively. Neither appears to be anything more than depth, but on another team they may not be anything more than practice squad material at best.
Need going forward?
There isn't a pressing need to add depth, but if the right opportunity presents itself, I wouldn't be surprised if the Lions made a move to bring in an offensive guard. That opportunity could come along during training camp when a player is released from another team or not until the final round of roster cuts, but this is one of the positions where you almost expect a new face to be brought in at some point.