According to Adam Schefter of ESPN, it's likely to happen. Schefter reports that Boldin, a free agent to be, and the Niners are "closing in on" a new contract.
At the age of 33, Boldin had one of the best seasons of his career and his first 1,000-yard season since 2009, catching 85 passes for 1,179 yards.
Boldin didn't have a dominant week-in, week-out season or anything. And he's older and slower. He doesn't separate from defensive backs. But he's still a physical beast and managed to produce at an age when you'd expect a decline in statistics.
You've got to assume the Niners aren't going to give Boldin a long, expensive deal. But clearly bringing him back to the locker room is a big priority for them next year.