The 35-year-old has been unable to add to his 463 appearances for the Pilgrims since September having undergone surgery.
"He's making progress," Argyle manager Carl Fletcher told the club's official website.
"He's had an operation which is always a big thing, whatever op you have.
"The lower back is an important part of your body and a lot of different injuries can come from it - it affects your hamstrings and your calves and all kinds of things in the lower half of your body.
"We're just taking our time and making sure he's right."