A year ago, wide receiver Christian Kirk was still preparing for his first NFL game, and like a typical rookie, preferred to be seen and not heard.

Larry Fitzgerald was the superstar of his position group, and Kirk dared not rock the boat.

"I was quiet when I got in," Kirk said. "He says now, 'Christian, you didn't even talk. Like, you didn't say a word. It was hard to read you.' … Fitz is older than me and he's been a guy I've looked up to, has been an idol of mine. So when you transition to him being a teammate, you have to work through that warming up period."

A year later, everything is copacetic. In fact, Fitzgerald has been the one asking to hang out with the second-year trio of Kirk, running back Chase Edmonds and wide receiver Trent Sherfield of late.

"That's their little crew," Fitzgerald said. "I'm the old man in the young crew. They let me in."

While Kirk and Fitzgerald have developed a healthy chemistry off the field, it's their performance on it that could make or break the Cardinals' offense in 2019.

Coach Kliff Kingsbury is expected to lean on the aerial attack starting Sunday against the Lions, but pass-heavy won't mean much without potent pass-catchers. Fitzgerald and Kirk were the team's two leading receivers a season ago and are expected to highlight the group once again.

It was a quiet preseason for both, by design, and on Sunday they should be unleashed.

"They're both great players, and we knew going into the preseason that we wanted to make sure they came out of it healthy, and they did," Kingsbury said. "Now we've got to make sure they have a role on our offense. I just love their preparation. I love the way they handle themselves at pros. They are what it's all about, really."

The two have many disparate qualities.

Fitzgerald is 36 years old and continues to play at a high level due to his big frame, craftiness and soft-as-velvet hands. Kirk is ascending at age 22 because his speed and quick cuts can put defenders on skates.

While the means to an end may be different, the results are similar.

"They're the best receivers I've guarded in a long time," rookie cornerback Byron Murphy said.

Fitzgerald has led the Cardinals in receiving the past four seasons, and it looks like a two-man race for the top spot in 2019. Kirk averaged more yards per game than Fitzgerald a season ago (49.2 to 45.9) but missed the final four contests with a broken foot.

Many are expecting a jump in production from his rookie year tally of 43 catches for 590 yards, including Kirk himself.

"I'm not going to sit here and be ignorant to it," Kirk said. "I know there's that expectation, and it's the expectation for myself, to be viewed as a higher-tier receiver. Every time I step on the field, I make sure that's what I'm putting on film, 'He's one of the top receivers in the NFL.' Obviously I have to back that up, starting Sunday and throughout the season. Whatever happened in camp, making those plays, that happened, but everybody does that in practice. When the lights shine bright, I've got to go out and make a statement."

Fitzgerald doesn't have anything to prove entering his 16th season, but continues to play because of the way Sundays make him feel.

"This is going to be my 230-something game, and I'm still as nervous as I've been for the last 230 games," Fitzgerald said. "I still get the butterflies. It means something to me. That's nice to be able to feel that feeling, that it's important and that it matters how I go out there and perform, how I lead, and how I help my teammates create opportunities for themselves. All of that is important to me."