In a video he posted on Twitter, Shazier said he plans to step away from the sport for now in order to explore other avenues in life:
Shazier suffered a spinal contusion in a game against the Cincinnati Bengals on Dec. 4, 2017, which required spinal stabilization surgery. While it was feared that Shazier could be paralyzed, he is now able to walk, but the 28-year-old determined he was unable to continue playing in the NFL.
At the 2018 NFL draft, Shazier walked across the stage to announce the Steelers' first-round pick.
Despite being unable to play, Shazier was a regular presence on the Pittsburgh sidelines last season, lending support to his teammates.
The Florida native was on the Steelers' reserve/PUP list in both 2018 and 2019. The team placed him on the reserve/retired list in March, which essentially foreshadowed the decision Shazier announced Wednesday.
While the four-year pro's career was cut short, he made a major impact in a short period of time. After the Steelers selected the inside linebacker with the No. 15 overall pick in the 2014 draft out of Ohio State, he appeared in 46 regular-season games and made 41 starts.
The 6'1", 230-pounder was named a Pro Bowler in both 2016 and 2017, and he arguably had his best statistical year in 2016 when he finished with 87 tackles, nine tackles for loss, 3.5 sacks, three forced fumbles, three interceptions and nine passes defended in just 13 games.
He also appeared in six playoff games for the Steelers, posting 42 tackles, two interceptions and two forced fumbles.
While Shazier's presence on the field has been missed, the Steelers had one of the NFL's best defenses last season, as they ranked fifth in scoring defense and yards allowed thanks largely to the continued emergence of superstar linebacker T.J. Watt.
Shazier essentially served as an unofficial coach during his time on the injured list over the past two seasons, so perhaps coaching with the Steelers could be in his future if he decides to get involved with football again at some point.