EDEN PRAIRIE, Minn.  — Minnesota Vikings defensive tackle Sharrif Floyd remains sidelined indefinitely, due to complications from surgery on his right knee done last September.

The painfully slow recovery process has raised questions about the viability of his career, and the Vikings have taken obvious steps this offseason toward a long-term replacement plan for their first of three first-round draft picks in 2013.

“It’s been hell. It’s hot down there, so you can only imagine,” Floyd said. “But I’m just fighting to stay positive and stick in there with my team. That’s the bright side of things right now.”

Floyd was on the field Wednesday watching his teammates take part in drills, but he’s still not cleared to participate. Floyd has missed 20 games over the last three years, including all but the opener in 2016. He had arthroscopic surgery Sept. 22 to clean up cartilage damage, before experiencing nerve problems around the knee from the procedure, according to multiple reports. Floyd has been unable to run at full speed.

“Just working out and training. There’s nothing more I can do,” he said. “I’m taking care of everything that’s in my power and controlling what I can control.”

Floyd, who spoke to reporters for the first time in more than six months, wasn’t willing to entertain any speculation about handing in his helmet. He said his return to action was “just a matter of when,” but he also said it’s “a little too early” to express confidence this will occur in 2017. Floyd declined to confirm the specifics of his condition.

“I feel like progress is being made,” he said. “Again, it’s just taking its sweet old time.”

The Vikings exercised before last season the fifth-year option on Floyd’s contract, which has become fully guaranteed for almost $6.8 million. His combination of size and speed has been a valuable asset for the defense when he’s been healthy, with the potential for more production as he reached his prime. But Floyd’s inability to stay on the field has held him back and drawn occasional public criticism from coach Mike Zimmer.

Asked last November why Floyd hadn’t already been placed on injured reserve, Zimmer said, “We didn’t think it was going to be, like, six years’ worth of hurt.”

While the Vikings have signed free agents Datone Jones (Green Bay) and Will Sutton (Chicago) and drafted Jaleel Johnson (Iowa) to join veteran Tom Johnson at Floyd’s spot, he has simply been trying to maintain a sense of optimism for his football future.