Cardinals safety Tony Jefferson (22) shows off his dance moves during a practice to fellow defensive backs Justin Bethel (28), Patrick Peterson (21) and Tyrann Mathieu (32).

Tony Jefferson was talking about how he came from the "bottom, bottom, bottom" when he got to the NFL, a one-time undrafted rookie.

It was suggested that Drake's hit song "Started From The Bottom," was about the safety. Jefferson could only smile.

"We heard Drake has some ghostwriters," Jefferson said. "I may have written that one for him."

Might he sing a few bars too? "I don't want to spill, man," Jefferson said, running with the joke. "It's $20,000 every time I rap. We'll leave it there."

Jefferson can afford to have some fun now. It wasn't so funny when he wasn’t chosen in the 2013 draft, after he left the University of Oklahoma after his junior season thinking he would most certainly get picked. But Jefferson pushed, helped by then-defensive coordinator Todd Bowles. Bowles too played in the NFL -- for a decade – as an undrafted safety.

"He made his mark, so I'm trying to do the same thing," Jefferson said.

He's fit into the Cardinals' deep well of safeties, a group diverse enough that all four manage to carve out playing time. There will be times when Jefferson, Rashad Johnson, Deone Bucannon and Tyrann Mathieu all are on the field at the same time.

"I think our versatility speaks for itself," Mathieu said. "We feed off each other.  It's obviously a competition (to play), but we're all in this thing together."

Johnson is the coach-on-the-field veteran. Bucannon is the hitter and the linebacker-in-training. Mathieu is the emerging playmaking superstar. Jefferson, who got a mere $10,000 signing bonus, has been the one who helped fill a huge void when Mathieu wasn't himself last season, and when Bucannon was needed in the front seven.

As far as he is concerned, Jefferson is still working up from the bottom.

"I haven't made the mark that I want yet," Jefferson said. "Especially on Madden. My rating's 77 so I've got a ways to go, man. I've got some things to work on and I'm excited about the process. Hopefully I'll have a good year this year."

HUMPHRIES BATTLES THROUGH TOUGH CAMP

It's been a rough training camp for first-round draft pick D.J. Humphries, who has struggled to find consistency. After coming into camp with the possibility he could win the starting right tackle job, coach Bruce Arians said this week Humphries will start the season as a backup.

"It's hard because I'm a competitor, and knowing I'm not playing at my best," Humphries said. "But all I can do is come out and try

and get better every day."

Humphries said he has absorbed the criticisms and just wants to use them as motivation. A college left tackle, Humphries has played there this week in practice – behind entrenched starter Jared Veldheer – so he can get used to both sides if he were to go into a game as the backup swing tackle.

"He's just got to mature," Arians said. "Talent is not the issue. It's maturity level, building trust."

Humphries did hurt his knee early in camp but refused to use it as an excuse.

"It was an injury but I'm not injured anymore," Humphries said. "I'm here and I have to start taking all the proper steps, start piecing everything together that I am supposed to be doing."

He knows his draft status will draw great scrutiny while he is doing the piecing-together.

"I'm a first-round pick," Humphries said. "Of course the spotlight is on me. That's what I expected coming in. But it's nothing I can't handle."

NO WEATHERSPOON, BUT CHRIS JOHNSON COULD PLAY

Both running back Chris Johnson and cornerback Jerraud Powers returned to practice Friday from their hamstring problems, but inside linebacker Sean Weatherspoon did not, still sitting with his bad hamstring.

Weatherspoon will join WR Michael Floyd (hand), G Mike Iupati (knee), T Rob Crisp (knee), S Ross Weaver (undisclosed), DL Ed Stinson (toe) and TE Troy Niklas (hamstring) of the players not making the trip to Oakland. Rookie nose tackle Xavier Williams, who is expected to make the team, came out near the end of practice with a left elbow injury and Arians said he will get an MRI.

Johnson wants to play Sunday night , Arians said, which is a good sign, but his status is a game-day decision. Powers, who had two interceptions Friday, will play.