INDIANAPOLIS — It's difficult for a player to be in the NFL for 10 years, yet still fly under the radar.
However, that's been the story for Anthony Castonzo, the Indianapolis Colts' starting left tackle since 2011.
No All-Pro selections. No Pro Bowls. However, according to Pro Football Focus, Castonzo has graded as a top-10 offensive tackle in the NFL in four different seasons, including two of the last three years ranking in the top five.
With that in mind, PFF's Ben Linsey released a list of each NFL team's most underrated player, and Castonzo was his selection for the Colts.
"The decision by Castonzo to stave off retirement for at least one more year, keeping one of the best offensive lines in the NFL intact, was one of the biggest developments in what has been a busy offseason for Indianapolis. The fact that Castonzo has never made the Pro Bowl is more of an indictment on the selection process than it is on Castonzo's play. He has been one of the most reliable left tackles in the game for years now, grading at 76.9 or higher in every season of his career excluding his rookie campaign in 2011. He may not be the best player on that offensive line anymore with the emergence of Quenton Nelson as one of the league's best young players, but Castonzo's consistently strong play is still underappreciated up front for the Colts."
As Linsey mentioned, despite still playing like he's in his prime, Castonzo entered the 2020 offseason contemplating his future and whether or not he would continue playing football. After giving it some thought, Castonzo decided to return, inking a new two-year deal with the Colts as a result.
That decision made for some happy teammates along the offensive line.
"I think we all were. I think Quenton (Nelson) was a huge advocate too. They both play on the left side together," Colts center Ryan Kelly told reporters recently about trying to convince Castonzo to stick around. "Obviously, Anthony and I have grown our relationship over the past four years and it would have been – it would really hurt to lose a player like him. Not just a player but such an incredible teammate.
"You know, having a guy like that – a 10-year veteran in the offensive line room is so crucial," Kelly continued about the importance of Castonzo to the Colts' line. "Ultimately, you see some guys retire early... It depends on every guy's situation. Obviously, if he was to walk away, 'Hey man, you had a hell of a career. Best of luck in retirement,' and we'll keep moving. That's the crazy thing about the NFL, guys come and go so quickly. You have to make it work, but obviously having (No.) 74 at the left tackle position is obviously going to give us the best edge to win games. I couldn't be happier he's back."
Castonzo was one of just two Colts offensive players to play all 1,077 snaps in 2019. PFF had him ranked as the ninth-best offensive lineman overall in the NFL with a grade of 81.3, and the No. 2 left tackle.
More specifically, Castonzo pulled in the sixth-best grade among tackles in pass blocking 84.4 after finishing as one of just 12 tackles to allow three or fewer sacks and one of 19 to allow 34 or fewer total pressures on the quarterback. He was also the least-penalized tackle in the NFL with just two flags, which is something that goes overlooked until an offensive lineman shows a real problem with remembering snap counts or holding defenders.
In the run game, Castonzo's game wasn't far off from his pass protection skills, finishing as the No. 8 tackle with a run-blocking grade of 70.2.
Castonzo has been the longest constant on an offensive front that has really turned itself around over the last couple of years. Since Quenton Nelson, Mark Glowinski and Braden Smith joined forces with Castonzo and Kelly in 2018, the Colts' offensive line has been one of the best, most balanced in the league.
Over the last two seasons, they rank ninth in the NFL in rushing offense at 120.3 yards per game, posting at least 150 rushing yards in 11 games in that time, including six 200-yard games.
In 2018, Castonzo's group allowed the fewest sacks in the league (18), and in 2019, the Colts had their most productive overall rushing attack since 1994.
Last season, the Colts' run game was clearly their strength. PFF graded them as the No. 2 run blocking unit (85.1) and No. 10 in run game grade (78.7). The Colts ranked seventh overall in rushing (133.1 yards per game), second in first downs converted by runs (131), fifth in carries per game (29.4), tied for fifth in runs of 20-plus yards (14), tied for ninth in runs of 40-plus yards (3) and 10th in runs of 10-plus yards (53).
The Colts also posted their fifth-best yards-per-carry average in team history (4.52) last season — thanks in large part to No. 74 off the left edge.
While Castonzo may be underrated on the outside, Colts head coach Frank Reich mixed no words when talking about Castonzo at the beginning of the offseason.
"We just made no bones about it, 'We want you as our left tackle. We are going to respect you and your decision to think about what you want to think about, but there is no one else we envision being our left tackle,'" Reich described when discussing Castonzo's future with him.
"We think he had an unbelievable year. I think he is the best left tackle in the league, I really do. I mean I think this guy is a stud player," Reich continued. "I think he had his best year of his career and I am looking forward to hopefully getting him back."