Former Raider Center Stefen Wisniewski has signed a 1 year, $2.5M 'prove-it' deal with the Jaguars. 'Wiz' was frequently looked at as an option by fans throughout his Free Agent adventure, but the team never expressed much interest. The Rams have had bad luck recently with injuries so you can't blame them for not pursuing Wiz.
Wisniewski played his entire rookie season with a torn labrum and had surgery following his rookie year to correct the issue. Surgery to correct another torn labrum after the 2014 season likely led to his prolonged stay on the unemployment line.
Wiz was the last serviceable Center on the Free Agent on the market. What the Rams lack with proven commodities at center, they make up for with youthful options. The team currently has Tim Barnes, Demetrius Rhaney, and Barrett Jones under contract.
Barnes filled in reasonably well in 2013 when filling in for Scott Wells. The Rams thought enough of Barnes to bring him back after non-tendering him. Rhaney has been praised frequently by Fisher, but was unable to do much last season due to injury. After a decorated career at Alabama, Jones has done next to nothing in the NFL and is largely an unknown.
Barring a trade - and with Snead you can never rule that out - the Rams not in position to draft a Center in the 1st round. Cameron Erving is the highest rated Center in the draft and he would be a reach at #10. After Erving, you have a cluster of players who could be selected in rounds 3-5. I'm not saying that those players aren't going to be good pros, but I question whether any of them would be an immediate upgrade over the group that the Rams have.
The only thing for certain is that the Rams starting Center next year is not going to have much - if any - starting experience.