I think they will need to consider trying to make up for the Humphrey debaucle in this Draft. I actually like Allen. He is not, as one article posted yesterday said, "one of the worst centers in the league". If they have quality guards flanking him he's a solid player.
But... I don't think that his knee thing is going away. Sure they could go into 2023 with him penciled in and Shelton as his backup. And that does give them the flexibility to Draft the best available OL on day 2 regardless of being a C/G/T. But if the best center in the Draft is sitting there when the Rams pick at 39 or 42 or whatever they should pull the trigger.