ORLANDO, Fla. -- The Oakland Raiders have signed 15 free agents since the start of the NFL's new league year March 14. They have re-signed four players, tendered all five of their exclusive-rights free agents, traded two players, flipped two of their six sixth-round draft picks into a pair of fifth-rounders and released another.

And that's not counting the moves Oakland made just before free agency began.

Truly, no team has been busier in free agency than the Raiders have been under Jon Gruden, with an assist to general manager Reggie McKenzie.

And yet ...

The biggest acquisition the Raiders have signed is receiver Jordy Nelson, who turns 33 on May 31 and is coming off a subpar season in which he caught 53 passes for 482 yards and six touchdowns.

Indeed, with the likes of running back Doug Martin, fullback Keith Smith, linebacker Tahir Whitehead, cornerback Rashaan Melvin, safety Marcus Gilchrist and offensive lineman Breno Giacomini, the Raiders have seemed to fill their roster with complementary pieces rather than centerpieces.

Yes, with Gruden Grinders.

So what, exactly, is a Gruden Grinder? I asked Gruden on Monday at the NFL owners meetings.

"I just like guys who love to play," Gruden told me. "Guys that will compete. Guys that will play for nothing. We haven't signed a lot of household names around the league, but we, I think, have brought in guys that are going to be consistent, everyday grinders, man. Guys that are going to compete their ass off and fight for inches and know what to do and set a tone.

"And I think that's important your first year, that you bring in some foundation players that can help you do that. So, yeah, I'm excited, man."

Then bring on receiver Griff Whalen, who actually signed before the new league year, tight end Derek Carrier, long-snapper Andrew DePaola, special-teams ace/linebacker Kyle Wilber, defensive end Tank Carradine, quarterback Josh Johnson, cornerback Shareece Wright and linebacker Emmanuel Lamur.

Not to mention re-signed defensive tackle Justin Ellis, tight end Lee Smith, quarterback EJ Manuel and free safety Reggie Nelson, who is very familiar with new defensive coordinator Paul Guenther from their time together in Cincinnati.

Raiders general manager Reggie McKenzie's job description may have altered a bit with the arrival of Gruden, though he insists he is enjoying it.

"The one thing about Gruden, I know exactly what he wants, which is great," McKenzie said. "I know exactly what his system, with (defensive coordinator Paul) Guenther, and I know exactly the kind of players they want at each and every position. That makes my job, really, a lot easier. Instead of trying to figure out what works best."

Was that, then, a problem with Jack Del Rio?

"Well, no, no, not to say that," McKenzie said. "But the communication is constant (now) and I'm not talking with just Coach Gruden. I'm talking about the entire staff and it's well received."

Still, middle linebacker NaVorro Bowman remains unsigned -- McKenzie said the Raiders want him back -- and there is something else troubling Gruden.

This whole hurry-up-and-wait game provided by the CBA that was instituted after Gruden last coached a game in 2008 has Gruden wringing his hands, what with the no-football-talk allowed between coach and player.

At least, not until April 9.

"We're making progress," Gruden said. "I like where we are. We've got a long way to go, but it's been tough, man. I've been head coach 65 to 70 days and I haven't been able to even meet my players yet.

"It's a challenge for all the new coaches, especially. Yeah, you've got to get over it. But you know, you have to come in, you have to evaluate the players, and you're not able to really ask them, 'Hey, why'd you do that? Or, 'Hey, what happened on this play?' And you've got to make some tough decisions. It's been uncomfortable; it's been uneasy. But I'm not the only one."