You kind of inadvertently hit the point. The Cards have good depth guys on the OL. The problem is they are starters for the Cards. I'll give Massie time and think he'll develop fine but he should be a depth guy and learning the position this year. Snyder is a swing player, depth guy at best. Batiste is a practice squad level player. Colledge and Sendlein, at best, are low level starters and most likley backups on teams with a good OL. Potter will likely be a career backup and provide depth, which is what you want from a 7th round pick. The Cards may be starting him as a rookie. Levi is mid-tier to low level starter and the Cards best OL. That should tell you all you need to know. We'll see about Kelemente.
It almost seems as if the Cards don't put any emphasis on the OG position. Lutui was their best in recent years and even when he was fat he stilled played well. Yet, he was run out town, albeit some of it was his own doing. I can't even remember the guy who played RG last year. Adam Snyder was signed to replace him so that tells you how bad he was. For this reason the #3 guy on my Cards draft wishlist, after Wilson and Te'o, is OG Chance Warmack. If Kelemente comes through, next year an OL of Brown, Warmack, Sendlein, Kelemente, and Massie would be a potentially good, young, cost controlled unit.