Running back (Adrian Peterson): At age 30, and returning from a 15-game absence last year, he's vowing to "shock the world."
Wide receiver (Mike Wallace): The Vikings think Wallace can give them the true deep threat they lacked last season.
Wide receiver (Charles Johnson): He's got good size for a split end (6-foot-2, 215 pounds), and he clicked with Bridgewater in 2014.
Wide receiver (Jarius Wright): After a career high in catches and yards, he'll be used all over the field in 2015.
Tight end (Kyle Rudolph): Can have a big year in Vikings' offense if he stays healthy; missed 15 games last two years.
Left tackle (Matt Kalil): His knees are healthy after surgery; now the Vikings need him to play like he did as a rookie in 2012.
Left guard (Brandon Fusco): He's recovered from a torn pectoral muscle and is moving from right guard in part to support Kalil.
Center (John Sullivan): The Vikings gave him a contract extension this summer; he turns 30 in August, but is smart, mobile and durable.
Right tackle (Phil Loadholt): He's coming back from a torn pectoral muscle, too, and needs a solid year at age 29.
Defensive end (Everson Griffen): Missed out on the Pro Bowl after 12 sacks last year; he was strong against the run in 2014, too.
Nose tackle (Linval Joseph): Improved at the end of last season -- Vikings are counting on him to anchor the run defense.
Defensive tackle (Sharrif Floyd): Vikings need him to stay healthy this year -- he could be on the verge of a breakout year if he does.
Defensive end (Brian Robison): Turned 32 in April, and missed most of OTAs with pectoral injury. Needs a good year to stick around.
Middle linebacker (Eric Kendricks): Second-round pick impressed in minicamp; coverage skills could get him the nickel job, too.
Strong-side linebacker (Anthony Barr): Was a Defensive Rookie of the Year candidate until a knee injury in November.
Cornerback (Xavier Rhodes): Played like an elite cover corner late last year; he could be asked to shadow top receivers this season.
Safety (Harrison Smith): Only player with at least three interceptions and three sacks last year; he'll move all over the Vikings' defense.
Kicker (Blair Walsh): Went through a rough patch late last year, but still has special teams coordinator Mike Priefer's trust.
Punter (Jeff Locke): Needs to be more consistent to keep his job in 2016; he had too many touchbacks last season.
Kick returner (Cordarrelle Patterson): Teams kicked away from him in 2014; looking to get his explosive touch back on returns.