Holt didn't play in 2010 after injuring his knee in training camp with the New England Patriots.
Holt said, "Some days I feel good and I think, 'Maybe this can happen.' But there are times when the pain and discomfort is there and it takes me back to reality."
He started working for the NFL Network at the end of the season, and knows he has a place there.
If Holt doesn't play again, that would create quite a list of first-time eligibles for the Pro Football Hall of Fame in 2015. Holt would join former Rams quarterback Kurt Warner, wide receiver Isaac Bruce and tackle Orlando Pace.
Each player's final season was 2009.
Reflecting on the good times, Holt said, "Special days in St. Louis. And I want to thank Rams fans for making me feel so welcome and loved while I was there. I'll always be grateful."
He finished his career holding several NFL records. He has the most consecutive seasons with at least 1,300 yards receiving (6) and 90+ receptions (6). He also reached 10,000 (116 games) and 11,000 (130 games) career receiving yards faster than any other player.
Holt has the second-highest receiving yards per game average for his career (77.4 yards/game), and he holds the record for the most receptions in a single decade (868, 2000-2009) and receiving yards in a single decade (12,594, 2000-2009).
The former NC State standout spent time with Jacksonville and New England following his long stay with St. Louis, and he chimed in on the current Rams.
"They've got it going," said Holt. "Sam Bradford is going to be very good in this league. They need to make sure they get the ball to Steven Jackson.
"They need to find some ballplayers to put around Bradford. Some receivers to help him out. I think 'Spags' (coach Steve Spagnuolo) knows what he's doing. They've got that defense flying. And I like the hiring of (Josh) McDaniels. He'll crank up that offense."