Mike Ehrmann/Getty Images
The NFL season began with the stunning early retirement of Indianapolis Colts quarterback Andrew Luck at age 29. It winds down with the stunning retirement of Carolina Panthers linebacker Luke Kuechly just a few months shy of his 29th birthday.
Now he adds his name to the growing list of elite NFL players to hang up their cleats young, joining the likes of Chris Borland (24), Rob Gronkowski (29) and Doug Baldwin (30).
Like with Luck, there's simply no replacing Kuechly outright on the roster.