Throughout the 2016 season, many folks wondered how Red Sox icon David Ortiz could walk away from baseball despite remaining such a dominant offensive force. After all, Big Papi hit .315/.410/.620 with 38 home runs and 127 RBI this year.

Ortiz, now 40, said he was done with the grind of baseball and dealing with all the nagging injuries. Even as a DH, Ortiz always seemed to be banged up. He's had heel problems for years, and now we know the full extent of his injuries.

David Ortiz played through tremendous pain later in his career. USATSI

Dan Dyrek, the team's coordinator of sports medicine services, told WEEI.com's Rob Bradford that Ortiz was "essentially playing on stumps" the last few years because his legs were so messed up.

From Bradford:

"He had tremendous problems that were built up over the course of the years," Dyrek said. "It became a situation where one more straw broke the camel's back. The traditional approach was to give him some time off, give him some anti-inflammatory medication and so on. That wasn't gong to come even close to cutting through to what the actual problem was. "It became more and more apparent that he was in a great deal of pain, so I was asked to get involved with that and examine him. He was in extraordinary pain. He was playing in warrior mode in order to get through it. Once we started talking to him and he opened up, he said his ankles were on fire, and that was a pretty good description of what was going on, clinically. The amount of pain was so intense."

Dyrek explained it was not one thing that caused Ortiz pain. He played through inflammation in his Achilles for so long that scar tissue developed between all the joints and ligaments in his foot and ankle. Ortiz took anti-inflammatory medication regularly, but that only helped so much. That's why the Red Sox gave him regular days off and removed him late in games whenever possible.

Later in his career, it got to the point where Dyrek would have to evaluate Ortiz pretty much every day and help him get ready to play. This pain is something he'll have to deal with the rest of his life too. No longer playing baseball will help, but only so much.