Indianapolis Colts quarterback Andrew Luck shocked the football world on Saturday night by announcing his retirement at the age of 29. Although his injury issues in the last few seasons have been well documented, fans were still left stunned after one of the most talented players in arguably the most important position in American sports walked away at such a young age.

Many doomsday columns will be written today about the future of the NFL, discussing how early retirements such as Luck’s represent the impending downfall of the sport. However, this is not one of those articles. Instead, this is an indictment of one area that the Indianapolis Colts and other NFL general managers consistently neglect: building strong offensive lines.

Ryan Grigson was hired as GM of the Colts in the offseason leading up to Luck’s first overall selection in the 2012 NFL draft. Throughout his five seasons as GM, he selected just three offensive linemen in the first three rounds of the draft and eight overall. Only two of the eight remain on the roster today, both as backups.

Zak Keefer, an Indianapolis Colts beat writer for The Athletic, recapped Luck’s injuries on Twitter after the news broke. Those injuries include torn rib cartilage, a partially torn abdomen, a lacerated kidney, a torn shoulder labrum and a recent strange lower leg issue that has been discussed throughout this year’s training camp. It’s one thing for a player to struggle with repetitive knee, back or shoulder problems, but Luck has suffered a wide variety of unique and uncommon injuries. The frequency and type of injuries indicate that Luck was not simply an injury-prone player. His early retirement was directly brought on by injuries that occurred because of the Colts’ complete neglect of the offensive line position during Ryan Grigson’s era as GM.

Following Grigson’s firing after the 2016 season, the Colts hired Chris Ballard as their GM, and he immediately began to correct the errors of his predecessor by developing one of the best offensive lines in the league. However, the damage was done. Luck’s recent leg problem was the last straw and marked the immediate end of his professional football career.

As NFL teams watch one of the league’s most talented quarterbacks walk away from the game at age 29, they must realize how Grigson’s poor offensive line planning was the largest factor that led to this and learn accordingly. One prominent organization in the league appears to have already been employing a strategy aimed at preventing situations like this from arising.

Along with a promising young quarterback, the Philadelphia Eagles have one of the best offensive lines in the league. In addition to possessing five quality starters along the line, GM Howie Roseman has put a significant emphasis on building depth behind them. When the Eagles won Super Bowl LII, future Hall of Fame left tackle Jason Peters was out with injury, and Halapoulivaati Vaitai had stepped into the starting role seamlessly. In this past NFL draft, the Eagles selected an offensive lineman, offensive tackle Andre Dillard, who is the presumptive replacement once Peters retires in the near future.

By forgoing the chance to select a player who would immediately step in and help the team in 2019, the Eagles invested in the future of arguably the most important challenge facing the team: protecting their young star quarterback.

While processing Luck’s stunning decision to retire, GMs around the league need to pay attention to what teams like the Eagles have been doing at the offensive line position. Some players have chronic injury problems that hinder their ability to have a long career, but Luck is not one of those players. His enormous potential as an NFL quarterback was derailed because of his GM’s complete neglect of the offensive line, and GMs around the league must take note to prevent a similar situation from occurring within their organizations.