Bly, who played for the franchise from 2003 to 2006 and was with the team during preseason last year, joined workouts organized by Lions players Wednesday and Thursday at Detroit Country Day School in the city's northwest suburbs, and he has looked good, according to Delmas.
"He might be 85 years old, but he can still keep up with us," Delmas told MLive.com. "Having him join our team would be very complimentary to our secondary."
Bly, who turns 34 Sunday, didn't play last season and is a free agent ready to sign wherever he's wanted once the NFL's labor situation is solved. He joined the Lions' sessions, which drew 37 players over four days, after receiving an invitation from safety Erik Coleman.
"He's an older cat that knows the game," said Delmas, a starter at safety since Detroit took him in the second round of the 2009 draft. "Obviously, he's played here before us, so he'd be able to get us out of situations that we've never been in before."
Delmas, 24, is returning from groin surgery in January, and he said the most difficult part of his recovery has been making sure he doesn't do too much.
"The only hurdle I have to pass is not try to push it too much," he told the Detroit Free Press. "That's something I did back at home, and I reinjured it a little bit.
"Like a month or so after I started training, I retweaked it because I thought I was 100 percent, went out there did a couple (defensive back) drills, tried to be competitive with the other guys. It was a minor setback, but I'm good now."
Delmas, who ran ladder drills and did position work at Thursday's workout, said it was "tremendously" beneficial to join teammates after rehabilitating for four months at his Florida home, that he's "about 85 percent right now" and will be fully ready to go by training camp.
"These workouts really got me back into the groove," Delmas told the Free Press. "Just seeing the guys is very satisfying, being that we don't know if we're going to play football next year. There's a high chance, but who knows?"
Delmas initially hurt his groin during a workout last spring, and it was sore all season, he said, although he wouldn't blame the injury for a drop in production from his rookie season.
"I think the toughest part of me getting through last year was practice up (until) the game," he said. "Because once game day starts, I don't feel nothing. But it was tough. Mindset-wise, I was down a little bit, but thanks to great coaching and great players around me, that kept me motivated to keep going."
Coleman, whom the Lions signed in February to compete with rookie Amari Spievey for the starting safety job opposite Delmas, impressed the former Western Michigan University standout.
"I don't know if you guys have seen him with his shirt off, but he's the Incredible Hulk," Delmas said. "He's jacked up. But most of all he's a smart player, and I think I'm having a good time with him back there, because he's a humble guy, and he likes to hit, and that's what I like to do also."