In what quarterback Sam Bradford referred to as a "dress rehearsal" for the regular season, the Vikings will host the San Francisco 49ers for their third preseason game on Sunday night. Here are five things to watch:

Two key Vikings debuts, one critical return: For the first time this preseason, the Vikings offense is expected to be near full strength. Left tackle Riley Reiff and running back Latavius Murray are set to make their Vikings debuts after missing the first two preseason games because of back and ankle injuries, respectively. Reiff and Murray practiced this week and should see at least some game action with the starting offense. Just as important is the expected return of second-year receiver Laquon Treadwell, who has practiced all week after being limited by a hamstring injury suffered July 31. All eyes will be on Treadwell while he starts in earnest his bid for a better sophomore NFL season. Left guard Alex Boone is expected to return after being held out last week in Seattle. Linebacker Kentrell Brothers also could make his preseason debut after injuring his hamstring in training camp.

Center of attention: Does Nick Easton remain the starting center? Or do the Vikings give rookie Pat Elflein another chance to lead the way? Easton and Elflein rotated first-team reps at center during practices this week with Boone returning to left guard. The Vikings maintain the starting job is still up for grabs, meaning Sunday night's game could go a long way toward the decision since most starters traditionally don't play in the preseason finale.

More plays for a confidence booster: Starters typically play about a half in the third preseason game, so Bradford and the offense should get plenty of time to establish a rhythm. And Bradford for the first time will get a full test drive with the expected returns of Reiff, Murray and Treadwell. They started to find a groove last week on the opening series in Seattle, before an 11-play, 76-yard drive was stalled by two red-zone penalties.

Meeting expectations: It sounds as if Datone Jones, the 2013 Packers first-round pick who signed a one-year deal with a $1.6 million signing bonus in March, is playing to keep his job. The converted linebacker still is catching up to the basics of his new position at defensive tackle and has been taking 11-on-11 practice reps behind reserves Jaleel Johnson and Shamar Stephen. On a macro level, the vaunted Vikings defense also should look to meet expectations vs. a rebuilding 49ers offense, which is starting quarterback Brian Hoyer and ex-Vikings right guard Brandon Fusco.

Specialist jobs in limbo: At least three specialist jobs remain up for grabs between kicker, punter and kick returner. Vikings special teams coordinator Mike Priefer wants to see the kicker and punter competitions play out through the last two preseason games, when kicker Kai Forbath or Marshall Koehn could separate themselves. Priefer recently said both are hitting field goals at around a 75 percent success rate during practice drills. Neither has missed a kick in the preseason. At punter, veteran Ryan Quigley and Taylor Symmank will continue to rotate. Running back Jerick McKinnon is expected to audition again at kick returner with rookie receivers Rodney Adams and Stacy Coley also in the mix.