The Georgia high school football season begins Thursday with the first of 171 games scheduled for the opening week. Here are some things to know about the 2018 season:

Best openers: Nine games this week match ranked teams, three that are part of the three-day Corky Kell Classic. Those are Rome vs. Marietta on Thursday at Rome's Barron Stadium, Tucker vs. Buford on Friday at Georgia State Stadium and Colquitt County vs. McEachern on Saturday at Mercedes-Benz Stadium. The others are Lovett at Greater Atlanta Christian, Tift County at Warner Robins, Woodward Academy at Westminster and Allatoona at Cartersville on Friday, plus Bremen vs. Rabun County and Burke County vs. Benedictine on Saturday at Georgia Southern.

Teams to beat: Seven of the eight defending state champions are ranked No. 1 to open the new season. Those are Lee County (AAAAAA), Rome (AAAAA), Blessed Trinity (AAAA), Calhoun (AAA), Hapeville Charter (AA), Eagle's Landing Christian (A private) and Clinch County (A public). The exception is North Gwinnett, the defending champ in AAAAAAA, though the Bulldogs are No. 4 and expected to contend again. But the No. 1 team in the highest class is Grayson, which features a record 10 of the top 100 senior college recruits in Georgia.

New teams: Four football programs have joined the GHSA football ranks, bringing the number to 422. Newcomers include newly opened Denmark of Forsyth County (Region 7-AAAA) and Cherokee Bluff of Hall County (7-AAA). Trinity Christian of Coweta County (5-A) made the jump from the Georgia Independent School Association, where the Lions were Class AAA runners-up last season. And ACE Charter of Macon (7-A) will play varsity football for the first time.

Reclassified: The GHSA did a mid-cycle adjustment resulting in the reclassification of 12 schools. Most notable among them were the lowering of Jefferson to AAA and Bremen to AA and the elevating of Benedictine to AAA. They are ranked in their new classes.

Team to watch: Marietta, which made the state quarterfinals last season for the first time since 1994, is loaded with college prospects and clearly on the rise. MaxPreps ranked the Blue Devils No. 15 nationally in its preseason poll. But the Blue Devils last month were forced to forfeit their eight football victories from 2017 when the GHSA ruled that two starting players were ineligible because of residency issues. Those players, both Division I recruits, can't play this season.  

Top recruit: There's disagreement on the state's No. 1 senior college prospect. Grayson linebacker Owen Pappoe, ranked No. 1 by ESPN, committed to Auburn on May 1. Upson-Lee's Travon Walker, ranked No. 1 by 247Sports, chose Georgia on July 24. Cedar Grove wide receiver Jadon Haselwood, ranked No. 1 by Rivals, has been committed to Georgia since he was a sophomore.

New coaches: Some 90 teams hired new head coaches in the offeseason. That's one in five, about typical. Among the new hires are Westover's Olten Downs, who won a state title at Creekside in 2013 before venturing into the college coaching; Veterans' Milan Turner, who won a state title at ECI in 2007; Thomas County Central's Ashley Henderson, who won three GISA championships at Valwood in Valdosta; and North Paulding's Jim Bob Bryant, who won three state titles in North Carolina.

Retired coaches: Howard's Barney Hester (340-167-9) and Gainesville's Bruce Miller (225-126) - who had ranked second and fourth, respectively, among GHSA head coaches in victories - retired. Hester is now athletics director for Bibb County schools. Rick Tomberlin (246-119) unretired and reassumes his third-place standing among active coaches in wins. Tomberlin is head coach at Appling County, his alma mater.

New official: The GHSA voted to add a seventh on-field official for the playoffs. The new official - a back judge - will be positioned behind the defense. The GHSA's decision resulted from a controversial play in the Class AAA championship game in which TV replay showed a Peach County receiver catch a pass that was ruled incomplete at the 1-yard line by an official positioned at the goal line. Calhoun got possession and held on to win 10-6.

Just in case: The GHSA added alternate dates for the eight 2018 state-championship games in case of interference from weather or soccer. Atlanta United will get dibs on Mercedes-Benz Stadium on Dec. 7-8 if the soccer team makes the MLS Cup championship game. In those cases, the football championships will be played on Tuesday, Dec. 11, and Wednesday, Dec. 12. Recent odds of United winning the MLS Cup were placed at 11-2, meaning soccer is a decidedly bigger threat than the kind of ice storm that postponed most of the 2017 state finals.