David Ortiz missed close to half of the 2012 season due to an Achilles injury suffered while jogging around the bases. It's certainly not how you would think about someone like Ortiz being taken down, but the human body is weird like that, and he had just enough awkwardness in the jog to damage one of the leg's most-important structures. While there was concern of a recurrence last year should Ortiz come back too soon, after a winter of treatment and plenty of rest, he feels fine now.
David Ortiz went through more agility drills today, says not worried about being susceptible to recurrence of Achilles injury #RedSox— Scott Lauber (@ScottLauber) February 22, 2013
To be fair, Ortiz didn't seem too worried last year when he was trying to come back, so excuse this state of cynicism that I'll use as a shield until he takes the field Opening Day. That being said, he is taking part in agility drills, and this mini-video from Peter Abraham's Twitter feed is eight seconds of Ortiz's Achilles not snapping in twine during them, so there's that.
Abraham also says that Ortiz expects to be ready by Opening Day, echoing general manager Ben Cherington's statements on the topic from earlier this spring. While he didn't play in Boston's doubleheader against Northeastern and Boston College on Thursday, he's expected to join the team in spring training games well before Opening Day is on the horizon.