"He's had some injections to try to alleviate some of the soreness," Kubiak said Sunday, according to ESPN.com. "The way I understand it we're trying to (work through) the injection process."
Foster received the first injection on Aug. 8. Kubiak said the injections have caused pain in Foster's legs. Kubiak wouldn't speculate about Foster's availability for Week 1 of the regular season.
"I'm not there yet because I see him work," Kubiak said. "I see what he's going through. I am concerned about repetitions. That's just me as a coach. ... We gotta do what we gotta do. We're trying to do the smart thing here."
None of this sounds great for Foster, who missed the majority of the team's offseason program while recovering from a strained calf. It also marks the second time the team has had to back off a publicly stated practice return date for the star.
Ben Tate remains the only back with any experience available to Kubiak, prompting the coach to say "the running back picture is concerning."
He's not wrong.