[OutsiderFan]

It's much better to play a Corner at Safety than a Safety at Corner.  In general, Safeties do not have the speed/quickness need to cover receivers in space or man-to-man.  Corners of course do (at least good ones).  It's quite common for NFL Corners to move to Safety to extend their career.  Ronnie Lott and Rod Woodson are two notable examples. 

What you would lose with a Corner playing Safety might be size, physicality, and sometimes the ability to "play centerfield" as a ball hawk, but Corners can be just as instinctive. 

As it relates to Stanford, Lyons and Carter both have pretty good size, so they both should be able to play Safety.  They were both ranked as Safeties coming out of H.S.

[OutsiderFan]

It's much better to play a Corner at Safety than a Safety at Corner.  In general, Safeties do not have the speed/quickness need to cover receivers in space or man-to-man.  Corners of course do (at least good ones).  It's quite common for NFL Corners to move to Safety to extend their career.  Ronnie Lott and Rod Woodson are two notable examples. 

What you would lose with a Corner playing Safety might be size, physicality, and sometimes the ability to "play centerfield" as a ball hawk, but Corners can be just as instinctive. 

As it relates to Stanford, Lyons and Carter both have pretty good size, so they both should be able to play Safety.  They were both ranked as Safeties coming out of H.S.