The 28-year-old Collins sustained a career-threatening neck injury at Carolina last season and had neck fusion surgery in September.
"It's still in process, which it has been," Thompson said during his pre-draft news conference on Thursday. "It's a process that continues. We don't have any determination at this point."
Collins and the Packers have not met to discuss his future and probably won't until after the draft, agent Alan Herman said.
If Collins can't play, Thompson may fill the position in next week's draft.
"I don't know," Thompson said about whether it would be nice to have some "determination" on Collins' future before the draft. "I think it's more important to make the right determination at the end of this. I'm sure he's anxious and all of our people are anxious, but I think it's more important being right than being fast."
Without Collins for much of the season, the Packers' pass defense struggled. The Packers probably could use help at safety. Internal options include M.D. Jennings, an undrafted rookie last year who played on special teams, and Anthony Levine, an undrafted rookie in 2010 who has served two stints on the practice squad.
Alabama's Mark Barron is the best safety in the class but figures to go long before the Packers pick 28th. Notre Dame's Harrison Smith is considered the second-best safety and a late first-round prospect.
"We feel like our roster is balanced enough overall," Thompson said. "We don't feel we have to target a particular position in the draft. That's not what we do, and we won't do it this year."