There is absolutely no mystery about whom the Arizona Cardinals' first three wide receivers will be this season.
Veterans Larry Fitzgerald and Andre Roberts will be joined by second-year man Michael Floyd as Carson Palmer's top three targets.
But there is still a lot of mystery surrounding what players will fill the other receiver spots when the Cardinals break camp.
Two players did their best to gain the attention of the coaching staff during Arizona's 17-0 preseason win over the Green Bay Packers at Lambeau Field.
Undrafted rookie free agents Jaron Brown and Charles Hawkins excelled in their first-ever NFL games, combining for nine catches, 132 yards and a touchdown.
Hawkins, who caught just 71 passes in a four-year career at Southern University, was excited about his debut, but is still focusing on improvement.
"It was my first NFL game and I felt like I had a good showing," Hawkins said Sunday. "But I still have to work on a couple of the little things, like my blocking and my assignments.
"I think I had a pretty good game."
Indeed he did. Hawkins had four catches for 92 yards -- a yardage total he matched or exceeded only five times during his college career. The 5-foot-8, 160-pound receiver knows his impressive debut is only one game and that there is much work to be done.
"The opportunity for me here is great, but everyone has that same opportunity," Hawkins said. "You've just got to keep on coming out here and working."
Brown is another one of the receivers trying to take advantage of an opportunity. The former Clemson Tiger caught the first pass thrown to him -- a fade in the end zone from second-string quarterback Drew Stanton -- for a touchdown in the second quarter against Green Bay.
"It was a nice game," Brown said. "It was a great experience, getting out there and getting the nervousness out."
Brown spent much of his college career at Clemson playing in the shadow of receivers DeAndre Hopkins and Sammy Watkins. In fact, the 6-foot-2 receiver had only 87 catches during his college days. He's done a lot in camp to emerge from the shadows of the other receivers fighting for a Cardinals roster spot.
Like Hawkins, Brown acknowledges the need to improve to become a more complete NFL receiver.
"I've got to get better with my blocking as well," he said. "Not only that, but run-blocking and getting the correct depth on routes, so that'll come in practice."