Welker suffered a concussion in last week's win over the Kansas City Chiefs, but Brady is confident that his former teammate and close friend will play in Sunday night's showdown.
"I've been around [Welker] long enough to know what he's all about," Brady said during an interview with WEEI sports radio in Boston. "He loves playing football, and if there's a chance for him to play, especially coming back here, he's definitely going to be out there. I've got no question about that."
Asked whether the two had spoken via text message about the possibility of Welker playing Sunday, Brady said, "No, no he didn't do that. But it would take an awful lot for him to miss the game."
Welker underwent a baseline concussion test Monday and, by league rule, cannot return to full participation in practice until Friday at the earliest.
While Brady is confident he'll see Welker in his first game back in Foxborough since departing for Denver as a free agent this past offseason, the star receiver's status remains unclear. Sources told ESPN NFL Insider Chris Mortensen that Welker is expected to be OK.
The 31-year-old Welker spent six seasons with the Patriots, catching at least 110 passes in five of those six campaigns and becoming an integral piece of their offense.
Welker and the Patriots went back and forth on long-term contract talks leading up to free agency. He signed a two-year contract with the Broncos, and the Patriots pressed forward and signed free agent Danny Amendola to a five-year deal.