Tackles have been the focal point of Leonard's game — for what it's worth, his 90 solo tackles are also the most in the NFL, and he also has 11 tackles for loss — but the South Carolina State product has also been able to affect opposing offenses in ways few other players around the league can, rookie or veteran.

One example: it's rare for a WILL linebacker to rack up a ton of sacks, just due to the very nature of their assignments and alignments. But Leonard on Sunday brought down Houston Texans quarterback Deshaun Watson for his seventh sack of the season, a figure that is second among all NFL rookies. Bradley Chubb, taken No. 5 overall by the Denver Broncos solely to rush the passer, leads all rookies with 12 sacks.

Need other impact plays? Leonard has four forced fumbles; that ranks tied for fourth in the NFL and is the most among all rookies. For good measure, Leonard also has two fumble recoveries.

Oh, and Leonard can also make plays in coverage. He has knocked down four passes and picked off Tennessee Titans quarterback Marcus Mariota back in Week 11.

It's the kind of impact Colts general manager Chris Ballard thought he could get out of Leonard when he took a chance on the FCS product with the 36th-overall pick in this year's NFL Draft, but because he spent much of the offseason workout program working off to the side with an injury, it took a while for the team to realize just what Leonard could bring to its defense.

Eberflus, who has been around a ton of talented linebackers during his lengthy coaching career, said he's never seen a player produce as a rookie at the level that Leonard has been able to this year.

"We certainly thought he had the attributes to do that (and) the physical traits to take that step and that leap. We have felt that all along," Eberflus said. "We just didn't know how fast the development would be there. That's really attributed to him. I mean he has accelerated his learning and (has) done a good job of picking up the package."

Eberflus said even though Leonard wasn't able to practice with the team during the offseason, he was putting in more than enough work so that when he did hit the field, he wouldn't have much of an adjustment.

That work has certainly paid off.

"When he first got here we had him early in the morning before everybody got here doing cone drills, alignment and assignment key technique stuff," Eberflus said of Leonard. "Me and Dave Borgonzi were doing that with him, then he would go to his treatment and all of those things and then he finally got in there during training camp.