Though it doesn’t seem like a big surprise given he had season-ending ankle surgery and was on a deal that didn’t include any guaranteed money for the final year of his latest extension.
Now, the Colts have to find his replacement for the 2021 season and beyond. Here are six options early in the process to replace Castonzo at left tackle:
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This is the outcome that is the most unlikely but seeing as Williams is potentially the best option in free agency, he has to be listed. Going after Williams won't be cheap even at the age of 32. He displayed elite play from the left tackle position in San Francisco during the 2020 season and could be a nice stop-gap for the Colts to extend their search for a long-term option. Williams is the least likely option for the Colts, but he's at least someone to consider if he does wind up hitting the market.
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This is an interesting one because the Colts could stay in house to find Castonzo's replacement. I wouldn't put all of my eggs in this basket, though, given the elite play that Nelson has displayed at left guard during his first three seasons. The Colts believe three-time All-Pro has the skill set to move to the edge if needed, but this should be viewed as a last resort measure. Frank Reich mentioned moving him to left tackle would be an option they consider but with a seemingly strong offensive tackle class in the draft, they may not have to resort to it.
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To the prospects. There will be several players the Colts could consider left off this list as the pre-draft process has only just begun. But Darrisaw is an intriguing prospect for the Colts if he falls around the range of the No. 21 overall pick. Here's what Joe Marino of The Draft Network had to say about Darrisaw's profile: "Virginia Tech offensive tackle Christian Darrisaw earned the opportunity to start for the Hokies as a true freshman and did nothing but improve for three seasons, developing into a dominant blocker in 2020. From a size, length, and mobility standpoint, Darrisaw firmly checks the boxes and should immediately become an asset to an NFL franchise in pass protection, outside zone runs, and utilizing his exceptional ability to pull and connect with moving targets in space. Like most young offensive linemen, Darrisaw has room to add functional strength to improve his overall power at the point of attack, but it’s far from a deficiency that is of major concern. The amount of technical growth Darrisaw has demonstrated throughout the course of his career is exciting when considering his starting point for the next level and how he peaked at the perfect time. It shouldn’t take long for Darrisaw to earn a starting role in the NFL and he has the upside to become a standout, franchise left tackle."
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Slater will be an interesting prospect because he could be viewed at any position along the offensive line. Some have him viewed as a tackle while others believe he may be best suited to dominate the interior. Regardless, Slater is likely to be among the top considerations at the No. 21 overall pick. Here is what Kyle Crabbs of Dolphins Wire and The Draft Network said about Slater's prospect profile: "Rashawn Slater is a scheme diverse and positional flexible prospect who should offer a little something to everyone depending on what specific needs and traits are prioritized for any given franchise. Slater, who opted out of the 2020 college season and has not played since the end of the 2019 campaign, is well regarded for his fundamentals and functional athleticism along the front. Slater manned the left tackle position for the Wildcats. For teams that don’t prioritize certain measurable thresholds, he appears to be a viable candidate to do the same in the NFL—based specifically on his work against 2020 No. 2 overall pick Chase Young in pass protection. But Slater’s ceiling is likely lowest on the edge and the further into the heart of the line he transitions, the higher his potential is to become a perennial Pro Bowl player and potential All-Pro candidate in my eyes. Slater has tremendous cutoff abilities and clean, patient footwork working space and the necessary functional strength to hold his own on the interior. The position flexibility he offers ensures he can be a part of any NFL offensive line’s combination of best five players to start up front from Day 1."
Left tackle Liam Eichenberg could be Notre Dame's highest selection in the 2021 NFL draft.
One of the prospects in the draft being praised for his NFL readiness is Eichenberg out of Notre Dame. It wouldn't be a surprise to see the Colts make another trip to South Bend given their last pick in Nelson, but Eichenberg may be one of the offensive tackles who are ready to play from Day 1. The Colts could certainly use that seeing as they are currently in win-now mode. Here's the draft profile from Kyle Crabbs on Eichenberg: "Liam Eichenberg is an NFL-ready starting left tackle who should find assimilating to the pro game fairly easy. Eichenberg isn’t the most fleet of foot and speed rushers with wide angles can test him off the edge, but sound fundamentals and footwork should have him positioned to contest such challenges with a fair amount of success. The ceiling for Eichenberg as a prospect is tied to the offensive philosophies of his future coach. He is best when releasing vertically at the snap in the run game and either double-teaming to the second level or stepping down to collapse and create a soft edge. Gap/power teams will unleash his power at the point of attack effectively and he’ll do well to create creases as guards pull or tight ends insert to lead the ball carrier through his gap. In all, Eichenberg is a part of a talented crop of 2021 offensive tackles and his ultimate place in the pecking order will come down to team preferences. He’s more impactful in the run game than he is in pass protection, but he was rather smooth protecting one of college football’s most unpredictable quarterbacks this past season, too.
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If the Colts wanted to wait until the second round of the draft, Faalele may be their choice to target. This is a possibility because there is also a chance the Colts try to draft a quarterback in Round 1. If that's the case, the new left tackle will have to wait at least one more round. Faalele has the size that will intrigue teams and when combining his movement skills, he has a high ceiling to be an anchor on the left side of the line. Here is the draft profile from Kyle Crabbs on Faalele: "Daniel Faalele projects as a viable starting offensive tackle at the NFL level despite some areas of improvement throughout his game. Faalele is a freakishly large athlete for the game and moves with more agility and grace than you'd ever expect from a man of his stature. Add in his raw size and it is clear that Faalele offers the "unteachable" dynamics of the position and will likely be coveted as a result of having all the tools in the toolbox and simply needing refinement on his technique. Opting out of the 2020 college football season lost Faalele some valuable repetitions in his player development but never the less he's shown enough instinct and feel for the position for teams to have comfort that he's still simply scratching the surface of what he can be as a blocker. Given Faalele's relative inexperience to the game — he was a former rugby player who has only two seasons of starting experience at Minnesota — Faalele's ceiling is unquestionably high. There's a dynamic of risk and reward here that needs to be weighed but teams with accomplished line coaches who are comfortable in player development should not shy away from the challenges that come with an investment here."