TEMPE, Ariz. (AP) Four rookies are playing a significant role in the Arizona Cardinals' success.

Running back David Johnson leads the team in touchdowns and wide receiver J.J. Nelson is a lightning bolt of a big-play threat. And on defense, nose tackle Rodney Gunter and outside linebacker Markus Golden have starting roles.

''We all talk a lot, try to help each other out,'' Johnson said.

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Three of them are from schools outside the Power 5 conferences - Johnson from Northern Iowa, Nelson from Alabama-Birmingham, Gunter from Delaware State. The exception is Golden, who played at Missouri.

Johnson is at the top of the rookie list. The third-round draft pick moved into the starting role with injuries to Chris Johnson and Andre Ellington. In Sunday's 27-3 win over St. Louis - Arizona's sixth victory in a row - Johnson rushed for 99 yards, in 22 carries, and caught a 10-yard touchdown pass. He has nine TDs this season - four rushing, four receiving and one kickoff return.

''He's an explosive player,'' offensive coordinator Harold Goodwin said. ''He's got size, he's got speed, he can catch. The sky's the limit for that guy.

Johnson has been a part of things all along for the offense, but he broke out as an every-down back against the Rams.

''A lot of people had confidence in me and I had confidence in myself,'' he said. ''The coaches helped me out a lot, getting me ready for that game.''

Johnson, at 6-foot-1, 224 pounds, brings a power dimension to the running game that Chris Johnson and Ellington couldn't provide.

Next up for him is a place on the big stage of Thursday night football, at home against Minnesota.

''I think all the nerves are gone,'' Johnson said. ''I'm calming down a lot more, getting used to the offense.''

Johnson wasn't the only rookie to catch a touchdown pass from Carson Palmer in St. Louis. J.J. Nelson, perhaps the fastest player in the NFL, had a 22-yard reception to cap Arizona's scoring drive the first time it had the ball.

Nelson, a fifth-round pick, has 11 catches, but most of them have been big gains. He's averaging 27.2 yards per catch.

''He needs to eat, first off,'' Goodwin said, joking.

Nelson, 5-10 and just 160 pounds, outran the secondary for a 64-yard touchdown catch in the team's Sunday night win over Cincinnati on Nov. 22.

On defense, the massive 6-foot-5, 305-pound Gunter, drafted in the fourth round, has impressed the coaches ever since he got to Arizona.

When Corey Peters went down with a season-ending injury in the opener, Gunter moved in as a starter. He has 21 tackles, three tackles for loss, 11 quarterback pressures and two quarterback hits.

Golden, a second-round draft pick, has started four games but played in all 12. He has 25 tackles, a forced fumble, 13 quarterback hits and 11 quarterback pressures.

''You have to know your plays a little more (than in college) and you have to use your technique,'' he said. ''Really, football's always the same, but when you get to this level, you have to be smart, you have to be mentally prepared at all times.''

As the regular season moves into its final weeks and toward the playoffs, the rookies will find out what the NFL is at its most intense.

''We talk about five-star players - Larry (Fitzgerald) and (Patrick) Peterson - all those guys that we know are big-time players,'' Goodwin said. ''These young guys have got to step up. It's December football. And so far, so good.''

Conspicuously absent from this rookie list is first-round draft pick D.J. Humphries. The big offensive tackle has been inactive every game.

Coach Bruce Arians insists Humphries is improving steadily, ''but he's not ready.''

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