Five who will define NFL offseason

Peyton Manning says he expects to return to the field, but we shall see. Ric Tapia/AP Images

Somewhat amazingly, we've already narrowed the remaining NFL field down to just four teams. Although there's no shortage of compelling storylines and matchups to dissect in the lead-up to Super Bowl XLIX, there are 28 teams that have already turned their focus toward the 2015 season. Their offseasons are under way.

During each offseason, there are a handful of players who "move the needle" and generate significant interest. Whether they're players set to become free agents, targets of trades, draft prospects, etc., these players have us talking, pondering and analyzing what their futures mean for teams -- or the league at large.

With that in mind, below is a look at five players who could define the 2015 NFL offseason:

1. Broncos quarterback Peyton Manning