"I don't want Wes to play for my own personal reasons. I've seen him get concussions. It scares me," Bailey told Fox Sports. "I think he can still play, but I don't want him to play because of these concussions.
"This thing is no joke. It's a serious thing when you start talking about your head. And for him to have to worry about that at a young age that he is now, he has to think about that for years to come, and I just hope he hangs it up and not strap it up again."
Welker, who played with Bailey over the past two seasons with the Denver Broncos, remains unsigned. The 10-year veteran, who also has played with Miami and New England during his career, has 890 receptions for 9,822 yards and 50 touchdowns over his career.
"I understand why he has that desire to play, he wants the ring," Bailey told Fox Sports. "He still has that hunger, I just don't want to see it."
Welker, who signed a two-year, $12 million deal with the Broncos before the 2013 season, saw his role diminish in 2014 after he suffered a concussion in the preseason -- his third in roughly a nine-month span after two in 2013 -- and serving a two-game suspension for violating the league's policy on performance-enhancing drugs.
Welker's 49 receptions in '14 were his fewest since he had 29 catches in 2005, and defenses no longer had to use double coverage on Welker as often. Even against largely single coverage, Welker was targeted just eight times combined in the final three games of the regular season as he did not find and/or create much room to work, and was targeted just twice in the playoff loss to the Indianapolis Colts.
The five-time Pro Bowl selection had five seasons with at least 100 receptions in his time with the Patriots and had a single-season career best with 10 touchdowns with the Broncos in '13.
ESPN.com Broncos reporter Jeff Legwold contributed to this report.