The Tampa Bay Buccaneers could have kept running back Doug Martin in town through the 2016 season, by picking up the standard fifth-year option embedded in first-round draft picks' contracts. As Rick Stroud points out, the Buccaneers declined to pick up that option. We know, because the deadline was yesterday.
Had the Bucs picked up his option, they wouldn't have been committed to paying him anything in 2016: the money would have been guaranteed for injury only, so they'd only have risked him suffering a season-ending injury that would have carried over well into next season.