Comparison is only natural when projecting NFL prospects.

Due to his height and build, Iowa State wide receiver Hakeem Butler has garnered a lot of comparisons to former Detroit Lions wide receiver Calvin Johnson. At the NFL Combine, Butler was listed at 6-foot-5, 227 pounds, very close to Johnson's 6-foot-5, 238 pounds.

In the build-up to the draft process, Butler was able to train with Johnson, as well as Anquan Boldin, something he really has cherished.

"Oh, yeah, Calvin Johnson, he's been my mentor through this whole thing," Butler said while speaking at the NFL Combine. "Him and Anquan Boldin. They've both been very pivotal the last two months. I've grown immensely."

When first meeting and training with Johnson, which was set up by Butler's agent, Butler had a very hard time keeping his cool.

"It was a surreal experience," Butler said. "Calvin Johnson, I had to keep my cool at first, you want to fan-girl a little bit. Someone I watched growing up. I kept my cool. I don't think he knows every word he gives to me, I'm hanging on it. It means a great deal to me. I hang on every word."

While many players may brush off the comparisons of themselves to NFL legends, Butler has taken it in stride. He acknowledged the similarities between himself and Johnson, not only citing the size but their similar work ethic. Butler said he and Johnson are both quiet, laid-back people with a chip on their shoulder.

In his four seasons at Iowa State, Butler saw his role grow each year. As a freshman in 2015, he did not see the field and was redshirted. The following season he would become a reserve wide receiver, catching only nine passes. 2017 was his breakout season though, catching 41 passes for 697 yards and seven touchdowns. In 2018, Butler was named second-team All-Big 12 after producing 60 catches for 1,318 yards and nine touchdowns.

His production at Iowa State has seen him fly up mock drafts, with some projecting him to be picked by the Redskins.

According to his Draft Network profile, Butler "offers a promising skill set in a vertical offense. Butler has phenomenal flashes in contested situations and as a vertical receiver, but needs to add further polish to his releases against press to consistently stack defenders in the NFL. Butler lacks quickness at the top of hard angled breaks but has the size to further develop himself and create separation for himself. Look for Butler to develop through his first 3 seasons and eventually be a starting X-receiver."

Butler entered the NFL Combine looking to prove people wrong about his speed. Butler's favorite route to run is a go-route, simply because he knows that he has the speed and size to beat cornerbacks downfield. Butler also knew that people had doubts over his speed, despite being one of the faster receivers in the Big 12.

"I mean, a lot of people see my 40 [and doubt his speed] and that's expected," Butler said. "You put me on tape and you just see long legs eating up space. You don't know how fast they're moving. But if you put me next to a small guy, you're gonna see the speed. I play fast. I firmly believe I play fast. I just got to show I run fast on the track, I guess."

At the Combine, Butler ran a 4.48-second 40-yard dash, which was 16th among the receivers who ran at the combine. Butler's basketball background has helped him with his agility and speed despite being one of the bigger wideouts in the Draft. In high school, Butler averaged double-digit points on his basketball team.

One of Butler's best abilities on the field is his ability to make big plays. Butler's 18 career receiving touchdowns are third all-time at Iowa State, and his 22 yards per catch in 2018 was third-best across the country. Butler's ability to make big-time catches and get yards after catch comes from his mentality.

"When the ball's in my hands, I got to score every time," Butler said. "Like, I think my redshirt freshman year I only had eight catches and every time I caught it I tried to score because you never know when that ball's coming back to you. Even when I became the 'man' or the go-to receiver, I never knew when it was coming back to me and that's how I treated it. I tried to score every time."

Butler's mentality has helped him on the field, as well as off the field. He has the right combination of confidence and determination to improve, especially since one of Butler's biggest criticisms in college was the amount of dropped passes -- 11 in 2018 -- that he had. Butler acknowledged the issue and has been working hard to fix it. Even if Butler is able to correct all of the flaws people see in his game, he wouldn't be happy with where he is.

"I would say I just have to keep working as a whole," Butler said. "I can't be satisfied. Even if I had 100 big catches in a year, I have to have 200. You can never be satisfied. So, I would say my whole game."

Although Butler has admitted that he needs to improve, and can never be satisfied, he still has the confidence necessary to succeed in the NFL.

"I think I'm the best," Butler said. "You can't be here at the Combine if you don't think you're the best player here."