Spiller, who signed a five-year contract in August 2010, is set to enter free agency later this month.
Spiller played in only nine games last season because of a broken collarbone, but he rushed for 300 yards and recorded 125 receiving yards.
His most productive season was 2012, when Spiller amassed 1,703 yards and eight total touchdowns.
Buffalo general manager Doug Whaley adressed Spiller's free agency last month. From the Democrat and Chronicle:
Whaley said the Bills are meeting with Spiller's agents in Indianapolis and, "We hope we can close the gap and get the deal done. There's going to be some work that has to be done, but I have confidence that we'll each come to the table with an open mind and we'll try to get a deal done that's great for both sides."