The 49ers fullback is now signed through the 2017 season, sure, but we now know for sure that he'll enter '14 completely healthy.
"If we were to start today," Miller said during a conference call with reporters on Thursday afternoon, "I'd be ready to go.
"It's been a couple weeks that this (signing) has been in the works, but I've been letting my agent take care of everything, and I was really focused on offseason training and rehab. I've kept the blinders on."
The 2011 seventh-round draftee injured his scapula and, as a result, missed San Francisco's final five games, including three in the postseason.
"That was really tough, especially the timing of the injury," Miller said. "I felt like I was hitting my stride and playing well. The team was shifting gears and getting ready for playoff mode. We had a lot of good things going. I couldn't have been more happy for the guys on the team but was definitely struggling standing on the sideline watching games and watching practice, moving through the playoffs.
"It's been great motivation for me in the offseason to get back better than ever and have a successful and healthy season this year."
Miller continued to excel as running back
Given the physicality of the position he plays, the former college defensive end said he was happy to have the security of a three-year contract extension.
"When the talks first started of doing an extension," he said. "I was excited about getting that underway and done before we moved into the year."
Miller has been training at San Francisco's Santa Clara-based facility. He returned home to Georgia for one week before resuming his rehab and recovery from his season-ending ailment.
"I've had a full, healthy recovery and a couple weeks of rehab," he said. "It's looking good. I'll be completely ready and 100 percent."
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