Preseason practice for the 2008 high school football season will start in just four days.

Locally, Thomas Jefferson, the defending WPIAL and PIAA Class AAA champion, Baldwin, Seton-La Salle and Brentwood will take the field for their first preseason drills on Monday.

All four will face different-looking schedules once the regular season kicks off at the end of August.

The reason?

The WPIAL has realigned its high school football conferences for the 2008 and 2009 seasons.

The biggest changes have been made in Class AA where there are four conferences instead of five --which means there is no need for a wild-card playoff team.

Last year there were 35 Class AA teams. This year there are 39.

Class AAAA has increased from 23 to 25 teams while Class AAA has shrunk from 28 to 27 teams.

Class A, meanwhile, has grown from 27 to 32 teams.

Thomas Jefferson, which posted a perfect 16-0 overall record in 2007, remains in the Class AAA Big Seven Conference -- along with holdovers Chartiers Valley, Elizabeth Forward, Trinity and West Mifflin.

The Jaguars won their 17th conference championship in 2007.

Two new teams in the Big Seven are Belle Vernon and Ringgold. Both competed in Class AAA last fall as members of the Keystone Conference.

They are replacing Peters Township and Keystone Oaks, which dropped to Class AA and will compete in the Century Conference.

The Century Conference has had a major shakeup with six new teams.

Seton-LaSalle, South Fayette, South Park and Steel Valley remain in the Century Conference.

They are joined by Bishop Canevin (up from Class A Black Hills), Cornell (over from Class AA Tri-County North), Keystone Oaks, Northgate (over from Class AA Allegheny) and Quaker Valley (over from Class AA Midwestern).

Brentwood, Burgettstown, Carlynton, Charleroi and South Allegheny have moved out of the Century Conference.

Brentwood moved down to the Class A Eastern Conference, and was joined by Carlynton, another former Century member.

The two other new Eastern Conference teams are Avonworth and North Catholic, both Class A Big Seven members last year.

Leechburg, Riverview, Springdale and Wilkinsburg are the holdovers.

Baldwin remains in the same Quad A conference and faces the same opponents, with one exception.

McKeesport switched to the Foothills Conference, while Peters Township moved up from the Class AAA Big Seven Conference.

Rounding out the conference teams are Bethel Park, Canon-McMillan, Mt. Lebanon and Upper St. Clair.