These are all unrestricted free agents. The Titans do not currently have a restricted free agent that is an original Titan. There are 2 exclusive free rights agents in Michael Preston and Brandon Barden who are not listed or polled since the Titans own their rights.
Wide Receiver Kenny Britt
2009 Drafted by the Titans Round 1 pick #30
45 games, 146 receptions, 2354 yards, 16.1 Y/R, 19 TDs, 3.2 R/G, and 52.3 YPG
While Britt is super talented, the production hasn't matched the promise. Will he get another shot with the Titans? I think it's unlikely barring an outstanding year that just doesn't seem likely.
Defensive Back Alterraun Verner
2010 Drafted by the Titans Round 4 pick #104
48 games (100%), 6 interceptions, 27 passes defended, 2 forced fumbles (1 TD), 177 tackles
Verner has been a stalwart on the Titans defense since his rookie year. I wrote last year he should be extended but the Titans have shown no inclination to do so. On the other hand, they have continuously drafted defensive backs and are currently experimenting with him at free safety. While I like Verner, it doesn't seem likely he will remain in a Titans uniform.
Defensive Back Robert Johnson
2010 Drafted by the Titans Round 5 pick #148
15 games, 1 interception, 1 pass defended, and 9 tackles
Johnson got significant playing time early on and boy was that rough. Despite that the Titans seem to like Johnson. I would still say he is a longshot to get a new deal.
Wide Receiver Marc Mariani
2010 Drafted by the Titans Round 7 pick #222
32 games, 819 punt return yards for 2 TDs, 92 kick returns for 2278 yards and 1 TD, 5 receptions for 24 yards
Mariani was a pleasant surprise drafted from the same college as Brandon Fisher, Jeff Fisher's son in 2010 but he quickly opened eyes as an outstanding returner on special teams. Alas, a terrible injury during the preseason in 2012 put him on injured reserves. He looks to be on the roster bubble and could be a roster casualty post training camp.
Quarterback Rusty Smith
2010 Drafted by the Titans Round 6 pick #176
3 games, 45 attempts with 23 completions for 234 yards, 51.1 completion %, 1 TDs and 4 INTs 29.3 QBR
Rusty Smith is a fan favorite but I think its unlikely he will remain in a Titans uniform. I think it's a real possibility he could be a camp casualty come August.
Offensive lineman Fernando Velasco
2008 Undrafted free agent signed by the Titans
Has played 48 games and was ranked as the #11 center by Pro football Focus following the 2012 season.
What a pleasant surprise Velasco turned out to be and what a testament to patience and waiting for your time and opportunity. He spent the large part of his first 2 years on the practice squad and played sparingly beginning in late 2009. Following an August 2012 injury to Eugene Amano, Velasco won the job and was one of the few bright spots on offense last year. He will compete with Rob Turner and 4th round rookie draft pick Brian Schwenke for the center position, but he is versatile and can play guard as well. Seems a likely choice to get a new deal but his age (28) may work against him.