If The Rod got some out of line $$$ thrown at him & he does not return..... Rams may have one similar type DB named Christian Bryant, S, 5-10, 193, Ohio State. Rod was UDFA & was short too. Bryant was a four-star cornerback recruit who quickly saw immediate playing time due to injuries & stepped into a starting nickel-back. Like Rod, Bryant has fluid athleticism with the play speed & feet of a former cornerback, but has the mentality and physical nature of a safety. Like Rod, Bryant has rangy athleticism allows him to cover a lot of ground and his instincts frequently lead him to being in the right spot at the right time in college. Bryant also has some other Rod stuff in him cause he closes fast with bad intentions, aggressively throwing his body around. The biggy, needs to stay healthy to prove he can be durable enough for the NFL.
I not sure I would move TJ McDonald back to the rear of this defense TJ just might fall asleep on the field. Mo Alexander is no deep safety has more ability close to LOS much like Mark Barron than Rod.
Rams fastest DB on the 2015 defense was Cody Davis 4.41 sec 40 yd dash as a 6-2 206 pounder. Cody has been a Ram since 2013 & has played in 33 Ram games. He knows Greggs defense. In college he was Capital One Academic All-America (first team)...Phil Steele All-Big 12 (second team)... All-Big 12 (second team). As a pro he has been playing behind Rod. It's hard to find big, physical safeties with speed and movement skills like Cody.
I think that Both Bryant & Davis should be given the opportunity first to fill the Rod post before spending big in UFA' cy or drafting a FS in this yrs draft. You might be surprised! At worse they could be a bridge this season until the 2017 draft.