Del Rio lashed out Monday at reports that suggested Sims-Walker is on the trading block.
"I actually called out one of the people that was involved in some of that being spread because that's garbage," Del Rio said. "False, not credible and it's disappointing to see stuff like that just go out be thrown out there haphazardly without anybody checking any sources.
"I'm disappointed that something like that would be out there for us to discuss. He's done a great job of continuing to play. ... We like the way he's working. There are no issues here. There are some being manufactured outside the building."
Sims-Walker has 16 receptions for 185 yards and two touchdowns this season. He expressed frustration last week after having no catches for the second time in four games, but made it clear he wasn't going to complain about it and that he just wanted a bigger role in the offense.
"I'd like to be more involved, but I don't make the play calls around here and I don't make the decisions to throw the ball," Sims-Walker said. "It's kind of like it's out of my control. I've just got to roll with the punches for right now."
Sims-Walker caught four passes for 46 yards against Buffalo, including a 7-yarder for a touchdown that put the Jaguars ahead for good in the 36-26 victory.