I could hardly believe what I was seeing during the NFL Draft.

Every mock draft I looked at had Andrew Billings going off the board in either the first or second round. He was one of the prospects in this year's class that I was most intrigued with, and I was expecting to hear his name called anywhere from late-first to mid-second round.

So when the first round came and went on Thursday without anyone taking the Baylor nose tackle, I assumed he would be one of the more sought after names the begin the second round.

Pro Football Focus ranked him as the sixth-best player available heading into Friday.

Then two more rounds came and went on Friday night, and Billings' name remained on the list of available players. At this point, I was expecting to hear that there was some video of him wearing a gas mask that I didn't know about -- because I thought, surely, a player of his caliber, who was widely regarded as an early-round pick, was not being passed over simply due to a lack of talent.

When the draft continued on Saturday, there was no breaking news about any off-field incidents or a new injury, and still teams continued to pass on him.

The notion was that his fall was due to his lack of pass rush ability.

Then, finally, with the 24th pick in the fourth round, the Cincinnati Bengals drafted him.

Billings the Prospect

The one thing teams can't dispute is that Billings is incredibly strong.

In fact, back in high school, he broke WWE superstar Mark Henry’s Texas state record with a 2,010-pound three-lift total that included squatting 805 pounds, bench pressing 500 pounds, and deadlifting 705 pounds.

He used that power on the field in college to flatten opposing offensive linemen and run right through them.

In the video above, he lines up at right defensive tackle, blows up the lineman in front of him, and then keeps going to finish the play with a sack. But the supposed knock against Billings is that he slid in the draft due to lack of pass rushing ability, so that must have been a rare sack for him, right?

Actually, he led Baylor in both sacks (5.5) and tackles for loss (14) last season. Among the nine defensive tackles picked in the first and second rounds of this year's NFL Draft, only two had more sacks than Billings -- and they both played two more games than he did. Only one of them finished with more tackles for loss than Billings.

Billings is the youngest player in the above chart -- he just turned 21 in March -- and he is still growing as a player. He and Robert Nkemdiche are the only players in the above group who increased their sack total during each year of their college career.

The Baylor nose tackle improved against the run each year as well. Among all FBS nose tackles, Pro Football Focus graded him 19th against the run in 2014 and 5th in 2015. He even showed the awareness, the speed, and the motor to defend against a screen:

This all-around ability and helped Billings stay on the field for 765 snaps last year -- second-most among all FBS nose tackles -- on his way to earning Big 12 Co-Defensive Player of the Year Honors.

Billings in Cincinnati

Here at numberFire, we have use an in house metric -- Net Expected Points (NEP) -- to measure the value added or lost on each play relative to league-average expectation level. Allowing a two-yard carry is generally acceptable, but if it comes on 3rd-and-1, then it was a negative play for the defense and allows the offense to improve its expected point total. NEP accounts for those types of plays, where as traditional yardage stats do not.

The Bengals' defense improved for the second year in a row, and their 20.19 Adjusted Defensive NEP, 42 sacks, and 4.3 yards per carry allowed all ranked 10th in the NFL last season.

All four starters on the defensive line are returning this season. However, not all of them performed well enough to avoid being possibly replaced this season.

Geno Atkins was once again the star of the unit, racking up 11 sacks and earning Pro Football Focus' fourth-best grade among interior defenders. Carlos Dunlap added 13.5 sacks and received Pro Football Focus' 19th-highest grade among edge defenders.

On the other side of the line, Michael Johnson was graded the league's 85th-best edge defender. The incumbent starter at Billings' nose tackle position is Domata Peko, who finished last season with a career high five sacks, but struggled against the run, and finished the season as the 96th-best interior defender.

Going into his 11th season with the Bengals, Peko has failed to play all 16 games in a season only once -- he missed five games in 2009. Billings has the opportunity to come in right away and take early-down snaps away from Peko while learning from him to improve his own game.

If Billings becomes a starter in year one and continues to improve his game as he has done during each year of college, he will leave the 31 other teams regretting the decision to pass on him.