Central Florida again shapes up as the nation's top Group of Five program heading into the season. Just not by nearly as wide a margin as the last couple of years.

The Knights haven't lost a regular-season game since 2016 and now must try to continue that roll without star quarterback McKenzie Milton, who suffered a severe knee injury in last year's regular-season finale.

UCF is trying to bounce back from a Fiesta Bowl loss to LSU that snapped the Knights' 25-game winning streak.

"We've got great belief in who and what we are as a program," UCF coach Josh Heupel said. "Our players are extremely confident. Since I've been here, I think our players have and probably always will have a little bit of a chip on our shoulder. I don't think that's a bad thing for our program."

UCF could face a major challenge from Cincinnati in the American Athletic Conference's East Division. Cincinnati returns the nucleus of a team that went 11-2 and beat Virginia Tech in the Military Bowl last season.

The final Associated Press Top 25 last season had UCF 11th and Cincinnati 24th. The other Group of Five conference to have multiple ranked teams at the end of the season was the Mountain West ,with Fresno State (18th), Utah State (22nd) and Boise State (23rd).

Here are six Group of Five programs that bear watching this season. For this list, we decided to include at least one school from each of the G5 conferences (American, Mountain West, Conference USA, Mid-American and Sun Belt):

APPALACHIAN STATE

Conference: Sun Belt

Notes: Appalachian State is hoping a coaching change doesn't end its string of three straight Sun Belt titles. Former North Carolina State offensive coordinator Eliah Drinkwitz took over as head coachafter Louisville hired away Scott Satterfield. Appalachian State returns nine all-Sun Belt players from last season, including the 2018 offensive player of the year in quarterback Zac Thomas. Appalachian State ranked fourth among all Football Bowl Subdivision teams in scoring defense (15.5) and sixth in total defense (288.0) last year. The Mountaineers have gone 41-11 over the last four seasons and have won at least nine games each of those years.

BOISE STATE

Conference: Mountain West

Notes: We're giving Boise State the slightest of edges over Utah State and defending Mountain West champion Fresno State in the league race. Fresno State and Boise State have met in the last two MWC championship games, with Fresno State winning last year 19-16 in overtime. The Broncos have the preseason MWC defensive player of the year in Curtis Weaver, who collected 9 ½ sacks last season. Boise State has won at least 10 games 11 of the last 13 seasons.

CENTRAL FLORIDA

Conference: American Athletic

Notes: UCF is seeking to win an American title and go undefeated in the regular season for a third straight year. The difference this time is the Knights don't have Melton under center. Darriel Mack Jr. replaced Milton but broke an ankle during the offseason and won't be ready for the start of the year, leaving Notre Dame graduate transfer Brandon Wimbush as the likely candidate to direct an offense that has been as explosive as just about any in the nation the last two years. Wimbush is competing with Dillon Gabriel and Quadry Jones. UCF must upgrade a defense that yielded at least 40 points in three of its final six games last year.

CINCINNATI

Conference: American Athletic

Notes: Cincinnati improved from 4-8 in 2017 to 11-2 last year with redshirt freshman quarterback Desmond Ridder throwing 20 touchdown passes and only five interceptions. Cincinnati also returns Michael Warren, who rushed for 1,329 yards last season. The Bearcats allowed just 17.2 points per game last year to rank ninth nationally in scoring defense. Cincinnati's schedule gives the Bearcats opportunities to grab the spotlight. The Bearcats host UCLA and visit Ohio State in the first two weeks of the season. UCF visits Cincinnati on Oct. 4 in a matchup that could determine which team plays in the AAC championship game.

MARSHALL

Conference: Conference USA

Notes: Marshall returns nine starters on offense from a team that went 9-4 and won the Gasparilla Bowl last season. Marshall brings back quarterback Isaiah Green, four starters on the offensive line and its two top rushers from last season. Channing Hames and Omari Cobb lead a defense that didn't allow any individual to rush for 100 yards last season. North Texas is another Conference USA team that bears watching.

OHIO

Conference: Mid-American

Ohio hasn't won a MAC title since 1968 but enters this year as the favorite to win the league. The Bobcats have gone 9-4 and have won bowl games each of the last two seasons. Quarterback Nathan Rourke threw for 2,434 yards and 23 touchdowns and rushed for 860 yards and 15 scores last season. The defense looks to build on its 27-0 Frisco Bowl victory over San Diego State, which marked the first bowl shutout ever recorded by a MAC program.