The Saints play their third preseason game on Friday night against Jacksonville in the Superdome, but interim coach Joe Vitt said after Thursday’s walkthrough they would treat it like their second exhibition since they had the extra one in the Hall of Fame Game. That means backups are likely to play most of the way.

Here are three position battles worth watching:

1)Garrett Hartley vs. John Kasay at kicker: This is the most significant one because a missed or made kick could determine the outcome of more than one game. Hartley, 26, entered preseason as the favorite because he is 16 years younger than Kasay, who made 28 of 34 field goals and all 63 of his extra points when Hartley missed last season with a hip injury. Nothing has changed. Kasay has missed two field goals through two preseason games, but there were extenuating circumstances on both. One was blocked with a terrific effort around the left side of the line. On the other, holder Chase Daniel put the laces in the wrong direction. At this point, Hartley likely would have to miss a bad one to keep this competition close.

2) Chris Ivory vs. Travaris Cadet for the fourth RB spot: Cadet, an undrafted rookie from Appalachian State, has been the revelation of training camp, catching a team-high 14 passes for 109 yards and a touchdown. Vitt said he created matchup problems for defenses with his pass-catching ability out of the backfield. Ivory has fumbled several times in practice, rushed for 30 yards on 17 carries and caught just one pass. Still, choosing Cadet over Ivory would be a bold move. Ivory, a powerful runner, rushed for 127 yards against Carolina in the 2001 regular-season finale and was fourth in the NFL in average yards per carry (5.2) in 2010. Cadet needs to excel Friday to make the decision tougher.

3) Junior Galette vs. Martez Wilson at DE: With Will Smith suspended for the first four games, the Saints have to determine their second starter at DE opposite Cam Jordan. Galette was a third-down pass rushing specialist last year, and Wilson is a converted linebacker, so both have little experience taking on blockers on running plays. A third candidate, Turk McBride, is out with a sprained ankle but should be back next week. Friday night is a good opportunity for Galette and Wilson to prove they are ready.

Follow Saints reporter Guerry Smith on twitter@CBSSportsNFLNO.