Bears tight end Adam Shaheen came to the NFL as a so-called athletic freak — a Rob Gronkowski-like matchup nightmare who steamrolled opponents at the small-college level in almost cartoonish fashion.

But through two unfulfilling seasons marred by injury, the 6-6, 270-pound Shaheen has realized there’s a missing component that turns athletic freaks into Pro Bowl tight ends: You still have to be a football player.

“Coming back last year [off injured reserve], that’s when I was like, ‘All right, you’re not always going to be able to outrun [people],’ and really figured out how to shake somebody off or look him off,” Shaheen said.

“I think this offseason you can really say, ‘Look at the difference in the way you ran this year vs. last year.’ Really understanding [the position] — not just being a big body, but actually being able to create a separation. I’ve always been good with catching the ball in traffic and getting open [while covered]. That’s always been a strong suit. But now actually just making it easier for the quarterback and having more separation — just being a better player.”

Five weeks into training camp and the preseason, Shaheen has not yet shown overt signs of that transformative development. He missed time early in camp with a back issue and will not play even a down in the preseason.

Shaheen is one of the biggest unknowns for the offense heading into the regular season. And while coach Matt Nagy admitted to being eager to see what Shaheen could do, he’s not so eager that he would play him in preseason games.

After all, Shaheen is a prime example of why so many teams are not playing their starters much in the preseason. He suffered injuries to his foot and ankle against the Broncos in the preseason last year that put him on injured reserve and limited his production when he returned. Shaheen had five receptions for 48 yards and one touchdown in six games.

“I’m [eager] to see what he can do,” Nagy said. “I wouldn’t quite say ‘anxiety’ — I got to see what he could do last year in the preseason. Then he got hurt and came back. I don’t think he was 100 percent.

“For me, the risk and reward with him knowing his background with the injuries — I feel better taking more off of him so that risk isn’t there. Hopefully, the reward comes with him not playing as much.”

And even Nagy admits Shaheen is an unknown heading into the 2019 regular season. It’s hard to tell where Shaheen is at this point.

“I can’t say one way or another; I really can’t,” Nagy said. “I don’t know. I truly don’t know. I don’t know if he knows that. We won’t know until we get going.”

Nagy hopes Shaheen can develop into a productive player, if not some semblance of the big-play threat he was touted to potentially be.

“I look at the glass [as] half-full, and I always try to give everybody the benefit of the doubt,” Nagy said. “From what I’ve seen in practice, where he’s at, I feel like he’s in a good spot. I don’t feel like we’re in a spot where we have to worry that he can’t help us.”

Shaheen likes to play football like everybody else, but with as much as he has to prove, he’s not too antsy about sitting out the preseason.

“Not after last year,” he said. “I mean . . . it was the third preseason game [that he got hurt]. I’m eager to actually put it together on a real Sunday, not just a training game or an OTA.”

First things first then for Shaheen. Heading into the regular season, he’s feeling good.

“Very, very good,” he said. “Maybe the best since coming in as a rookie. I’m very excited to get out and play some football.”