A day later, the Raiders told veteran defensive end Bruce Irvin they were releasing him.
Yeah, there is a youth movement afoot in Oakland, so to speak, and with the Raiders 1-7 at the season's midway point, it is time for the newbies to assume new roles.
"He was just telling us that he needs more," rookie defensive end Arden Key said of Gruden's message.
"He needs more from his rookies. More. More. More. He said we're doing pretty good but he needs more and we need to lead the league in effort. And we're not doing that as rookies running to the ball and things of that sort. So, it was really a wake-up call."
Gruden may have been speaking to all of Oakland's rookies, but the missive may as well have been aimed at youngsters on the Raiders' defensive line. Because it was not that long ago when Key and defensive tackles P.J. Hall and Maurice Hurst were drafted to team with Irvin and Khalil Mack to present a more formidable pass rush.
But Mack, who was in a holdout that had no end in sight, was traded to the Chicago Bears on Sept. 1, and Irvin, well, he struggled as the Raiders' primary pass-rusher. Because even as he was leading the team with three sacks, Irvin had just six tackles, and played just nine defensive snaps against the Niners.
As a team, the Raiders have an NFL-low seven sacks, or 24 fewer than the league-leading Minnesota Vikings. In fact, 10 players in the league have more sacks than Oakland does as a team.
Hurst has two sacks with Key and defensive tackle Clinton McDonald having one apiece. And that's it.
Smith talked with the Raiders on Sunday night and was on a plane from his Dallas home Monday morning in time to practice.
"I'm sure they want to plug and play," said Smith, who had a combined 13.5 sacks his first two NFL seasons with the Tampa Bay Buccaneers, but none since suffering a torn ACL early in the 2016 season.
"I've got a ton of confidence in myself. Obviously, I've made a ton of plays in this league. ... These guys see something in me coming up here and giving me a shot to go out here and do what I do."
Smith has a familiar face in Oakland in McDonald, who signed with the Raiders after the season opener following four years in Tampa Bay. Smith is also familiar with the Raiders' 4-3 defensive scheme.
"Been at the top and now I'm trying to work myself back up to be the player that I was," Smith said. "It took a little time to get back to feeling like myself. Right now, I feel the best I've felt in a very long time. Now it's on me to go out there and put that product on the field.
"I'm going to be the best Jacquies Smith. That's my goal, to go out there and produce and do it fast."
Ealy, meanwhile, had not shown up to the Raiders' facility by practice on Monday. He has 15 career sacks in four seasons, with five in both 2015 and 2016 for the Carolina Panthers.
The Raiders should also be getting reinforcements on the defensive line in the coming days and weeks with Eddie Vanderdoes primed to be activated from the PUP list after suffering a torn ACL in last year's season finale. Justin Ellis, who suffered a foot injury in the season opener against the Los Angeles Rams that forced him onto injured reserve, should also start practicing soon.
Vanderdoes said he has been working at both the 3-technique and nose tackle.
"Whatever they want me to do," Vanderdoes said. "If they want me to dominate the run game, I'll do that. If they want me to play on passing downs, I'll do that. Whatever they want me to do, I'm down for it."
Yes, his knee feels fine. Even if his feelings are a bit bruised with Irvin being shown the door.
"I mean, s---, that was my dog right there, I like Bruce a lot," Vanderdoes said. "That was one of my big homies, him and Khalil. But at the end of the day, business is business and you've got to do what you've got to do. I mean, I've got to keep going about my business, D-line's got to keep going about our business but, really, that's none of our business, what happens to guys on the team. So we've got to keep pushing."
And some encouraging words from Irvin.
"He just said, 'Keep going, it's your time now, this is going to be your team now. Think of it as your team and your D-line now,'" Key recalled Irvin's parting words.
"I just want to take the D-line to next level."
Does he have any other choice?
"They're rookies," said defensive end Frostee Rucker, who is in his 12th NFL season. "We put a lot on their plate and that's because, in the future, this is going to be their team. They have to come along and they have to play and ... they're learning. That's the key to this -- they're building their own foundation on how to work, how to be accountable, how to be on time. They'll get stronger in the weight room, they'll learn how to get more physical at the point of attack.
"These guys are playing and those are valuable reps."