Sometimes I scratch my head as I hear calls for a new LOT and/or a new Center.
Shelton is a very good Center. No snap screw-ups, very few penalties for holding or otherwise, quick out of his stance and has good short area quickness to get to the 2nd level block, seems to make good Oline calls, is very consistent, stays healthy, etc. Is he an All-Pro? No. But you don't need an All-Pro.
LOT is similar. Jackson has done a really good job. He is fairly consistent and he stays healthy. He's young and still developing. All Olinemen get better with age and experience, and the longer a 5 person unit can stay intact the better the unit plays. We could spend a first rounder on LOT and have no reasonable assurance that the new kid would be any better.
While for me Dotson is the key for keeping the excellent unit intact, keeping Shelton provided someone doesn't make a nutty offer, and tendering Jackson is a no-brainer.