INDIANAPOLIS — In the NFL, if your offensive line play is top-notch, it opens up endless possibilities for your offense.
For the Indianapolis Colts, they have focused on building a line that allows them to work without restrictions, and one of the most critical factors to that is their offensive tackle duo in Anthony Castonzo on the left side and Braden Smith on the right.
Since the pair came together in 2018, the Colts average the ninth-most rushing yards per game in the NFL (120.3) and have allowed the third-fewest sacks (50).
While Castonzo is closer to the twilight of his career, he's still playing as well as ever, and Smith has shown outstanding growth as he now enters his third year in the league.
Ben Linsey of Pro Football Focus recently compiled a list of the top offensive tackle duos in the NFL, and Castonzo and Smith came in at No. 4 on the countdown. Linsey writes:
4. INDIANAPOLIS COLTS: LT ANTHONY CASTONZO AND RT BRADEN SMITH
One of the more underrated developments this offseason was Castonzo's decision to hold off on retirement and return to what has become one of the better offensive lines in the NFL. Castonzo hasn't been selected to a Pro Bowl in his nine-year NFL career, but he has consistently been one of the better pass-blocking left tackles in the game while still providing solid play in the run game. He has finished with an overall grade below 76.9 only once in his career, his rookie 2011 season, and he's one of just eight tackles to put up pass-blocking grades of 80.0 or higher in each of the past two seasons on 250 or more pass-blocking snaps. His return is big for the Colts in their pursuit of an AFC South title.
Smith, meanwhile, impressed from a grading perspective in his second season out of Auburn this past season. He still has some things to work on in pass protection — finishing the 2019 season with a 68.1 pass-blocking grade — but his 86.4 run-blocking grade was one of the best marks in the NFL. Considering young tackles generally don't reach their peaks until three or four years into their careers, Smith's improvement from 2018 to 2019 bodes well for his prospects in 2020. The results we saw from him as a run-blocker certainly bode well for Marlon Mack and the newly acquired Jonathan Taylor on the ground, too.
When contemplating the effectiveness of the Colts' offensive tackles, you've got to start with the elder statesman, Castonzo.
The Colts' blindside protector since 2011, he had one of the better years of his career in 2019 as he finished as PFF's fifth-best offensive tackle, and the No. 2 left tackle, with a grade of 81.3.
It was the third-best overall grade of his career after he played in all 1,076 offensive snaps for the Colts.
You want your left tackle to keep pass-rushers out of the quarterback's bubble, and that was Castonzo's calling card once again last season.
His grade of 84.4 in pass protection was sixth among offensive tackles after allowing just 34 total pressures all season, which included 26 hurries, five hits and three sacks. Castonzo was one of only 12 starting offensive tackles to allow three or fewer sacks, and he wasn't too handsy and aggressive with defenders either, as his two penalties were the fewest among all tackles.
With the Colts having a smashmouth, run-heavy approach on offense, Castonzo was a major piece of that puzzle. His run-blocking grade of 70.2 was eighth-best among tackles, and third among left tackles.
Castonzo and Smith complement each other quite well. While they both have a well-rounded game, Castonzo's strength is pass protection while Smith's strength comes as a run blocker.
According to PFF, Smith was not only the seventh-best offensive tackle in the NFL last season (79.8), but he was the third-best run blocker among them with a grade of 86.4.
Smith ranked 26th among tackles in pass-blocking and 12th among right tackles with a grade of 68.1 after allowing 46 pressures on the quarterback, which specifically ranked 14th among right tackles, including 30 hurries, nine hits and seven sacks. However, just like Castonzo, Smith plays clean and doesn't put his team in holes, as his five penalties in 2019 were the fifth-fewest among tackles.
As a pair, Castonzo and Smith were very reliable to run the ball behind in 2019. The Colts ran the ball behind or to the outside of the pair 193 times for 831 yards (4.3 avg.), six touchdowns, 49 first downs and 21 runs of 10-plus yards.
The Colts had one of the truly high-powered rushing attacks in 2019. It was the first time since 1994 that they hit the 2,000-rushing yard mark, and they posted their fifth-best yards-per-carry average in team history (4.52).
PFF graded the Colts offense as the second-best run blocking unit in the league with a grade of 85.1, and 10th in rushing overall at 78.7.
Their offense ranked inside the top 10 in firsts downs by rush (second, 131), percentage of first downs by rush (second, 27.8), runs of 20-plus yards (fifth, 14), overall rushing (seventh, 133.1 yards per game), runs of 40-plus yards (tied-ninth, three) and rushing touchdowns (tied-10th, 17).
The Colts' offensive front wasn't too shabby at keeping pressure away from the quarterback either, as they ranked 13th in pass blocking (75.1) and were tied for allowing the ninth-fewest sacks (32).