Alex Mack is walking away from pro football on his own terms. Mack, who was selected to his seventh Pro Bowl in 2021, is retiring following a decorated 13-year career, he officially announced on Friday.

"After 13 years and 204 games for three teams, I have decided to hang up my cleats," Mack posted. "I am so grateful to the game of football and everything it has given me. From the very start it helped shape who I am and taught me life lessons. I started to play football because it was fun and that never changed. 

"Thank you to the fans. You have been with me on an incredible journey across the country. Thank you to Cleveland, Atlanta, and San Francisco; I loved living in these cities and will miss their dedicated fan bases. Thank you to all the coaches, who tolerated my stubbornness and taught me as much as they could. I always tried to hold up my end of the bargain and never let anyone doubt my effort.

"Thank you to teammates and opponents. We are forever bound by our competition at the highest level and by our full commitment to our craft. I think I'll miss the O-line rooms the most; always a special collection of men willing to put in the work together, in near anonymity, for the good of the team. Thank you to friend and family. The demands of pro football can make a career appear selfish, yet, you supported me in my passion and rode with me for the ups and downs. I couldn't have done it without you.

"This really is more 'thank you' than 'goodbye'. From draft night to the final whistle, I will carry these special memories, and each of these treasured relationships, with me into my next chapter. All the best, Alex."

Mack, 36, spent the 2021 season with the 49ers after spending his first seven seasons in Cleveland and the next five in Atlanta. Including the playoffs, Mack made 20 starts last season while helping San Francisco reach the NFC Championship Game. 49ers coach Kyle Shanahan had previously kept the door open for Mack to resume his career in San Francisco should Mack have decided to play in 2022. 

"Football's not the easiest thing to do, no matter how much you enjoy the competition, and he's up there in age," Shanahan said in May. "But in terms of how he looks on tape and how he was [last season], everyone knows he can still play."

A Los Angeles native, Mack played collegiate at California and was selected by the Browns the 21st overall pick in the 2009 NFL Draft. A model of durability and consistency, Mack did not miss a start -- or game -- during his first five seasons. He was named to his third Pro Bowl in 2015 after missing 11 games the previous season after breaking his fibula.

Mack started a streak of 90 consecutive starts in 2015, with his run lasting until Week 16 of the 2020 season. In 2016, his first season with the Falcons, Mack was named to his second of four consecutive Pro Bowls while helping Matt Ryan win league MVP. Mack also played an integral role in Atlanta reaching the Super Bowl for only the second time in franchise history. 

Mack remained a constant staple in the Falcons' lineup until he signed with the 49ers last offseason. Mack's presence helped San Francisco finish seventh in the league in rushing and fifth in rushing touchdowns. The 49ers also boasted the league's top-ranked red zone offense. 

Including the playoffs, Mack started in each of his 204 NFL games. Along with his Pro Bowl selections, Mack's individual accolades includes being part of the Hall of Fame All-2010s Team.