SI writer predicts one free agent to follow Kellen Moore

Don’t understand the Guard talk, there are probably a hundred Tackles that can be excellent guards in the NFL. Tackles are usually the best athletes on the offensive line and because they may have shorter arms or their 40 time is too high they aren’t getting picked to play tackle at the NFL level. The pool for Guards is astronomically larger than Tackles. Remember Carl Nicks and Jahri Evans were Tackles in College.
Yeah I don't dive the deepest into draft classes but I heard this draft is full of tackles well suited to play guard.