It's hard to compare NFL players across eras, and from different positions. It's hard to compare Dick Butkus' dominance at linebacker in the 1960s to Deion Sanders as a shutdown cornerback in the 1990s, for example.
But whatever the criteria, Aaron Donald is in the conversation for greatest defensive player ever.
The Los Angeles Rams defensive tackle retired Friday with a nearly immaculate résumé. He played 10 seasons and made 10 Pro Bowls. He was first-team All-Pro eight times, including his final season. He was a three-time NFL Defensive Player of the Year, tying a record.