Depends.
Is Leary going to play during the regular season up to the level he showed before his injury?
Same with Free, who has given reason in the past for us to be suspect?
I expect Smith to be mostly solid, with the potential to become great. I've seen no reason to doubt Frederick will be mostly solid, with the potential to be great.
And I think if those four play like they have so far, Dallas can plug in one of several players in the final guard spot and still make the playoffs. I'd prefer they get a bona fide guard like Waters just to ensure it has the best five it can possibly get for this season, but I don't think not getting him will doom the line (unless injuries decimate the starters).
I am interested in see how the combination of Free at guard and Parnell at tackle works out as well. I don't like messing with Free when he appears to be back in a groove, but I will at least acknowledge that starting both of them
could give us our strongest line combination (if Leary gets back to replace Bernadeau).