6. Alex Mack
Alex Mack meant so much to the Atlanta Falcons after signing with them in 2016. He was as durable as anyone and was a total warrior which is why it was disappointing to see him leave after he missed his first two games with the team in 2020.
Mack went on to reunite with Kyle Shanahan in San Francisco and remained one of the best centers in football. He was named his seventh Pro Bowl during his lone season with the 49ers.
The plan for the Falcons was to replace him with a younger guy and that younger guy was Matt Hennessy. Mack only played one more season after he left Atlanta and it would have been nice to have him during his final season to be the starter at center while mentoring Hennessy.