The Pennsylvania Interscholastic Athletic Association, the governing body for high school athletics in the state, has released the classification breakdowns for sports for the 2010-11 and 2011-12 school years. Here are the numbers for football:

Schools with 513 boys or more in the top three grades will be Class AAAA; 512-311 will be Class AAA; 310-185, Class AA; and 184 and below will be Class A.

As was suspected, Central Valley, the merger of Center and Monaca high schools, will be in Class AAA. In fact, Central Valley, with a boys' enrollment of 339, is larger than Blackhawk (321) and not too far behind Hopewell (356).

If no school elects to play up from Class AA to AAA -- schools do not have to inform the PIAA about that until next month -- the WPIAL will have 30 Class AAA teams. That would make for four conferences, two with seven teams and two with eight. It would just make sense for Central Valley to move into the Parkway Conference, giving it eight teams.

Northgate, which competed in the Class AA Century Conference, is just under the cutoff and could compete in Class A next season. In fact, the Century Conference will have a different look because Sto-Rox and Bishop Canevin can also play at the Class A level and Cornell will drop to Class A with the ending of the co-operative agreement with Our Lady of the Sacred Heart. That's four conference schools that could play in Class A.

Nothing will change in Class AAAA unless a school decides to play up from Class AAA, which isn't likely. No school has done that in recent years. There are still 25 Quad-A teams in the WPIAL.

One final note: Blackhawk, which used to be one of the larger Class AAA schools in the WPIAL for football, is now fifth from the bottom. Only Derry Area, South Park, Valley and McGuffey will be smaller next year and Valley, McGuffey and South Park competed in Class AA this season.

Fans often question why the WPIAL schedules playoff games at certain schools when there seems to be a perfectly good stadium that would be an easier drive for the teams involved.

Well, there's a reason. Schools are not always available as playoff sites.

"The reality is that this is play season," said WPIAL executive director Tim O'Malley, the man responsible for procuring neutral sites for quarterfinal and semifinal contests.

Play season?

"That's right, a lot of schools have their plays at this time of year," he said. "We were looking to hold games at Baldwin and at North Allegheny this weekend but both have school plays."

The problem is with the competition for parking spaces in school lots. So, O'Malley had to look at some alternate sites.

"We were looking to have Hopewell and Hampton at North Allegheny but when that wasn't available, we had to try and find a place that was close for both of them," O'Malley said. "The same thing with Bethel Park and Woodland Hills. We were looking at Baldwin for that one, then got the call they have a play there this weekend."

Hampton and Hopewell will be played at Montour, which was refurbished prior to this season. With Beaver Falls and Aliquippa playing at Ambridge, O'Malley also had an issue finding a site for the North Catholic-Rochester Class A game.

"You look down toward town [Pittsburgh] and there's nothing there," he said. "So we looked at Mars, which Rochester fans can get to going out the back way through Cranberry and North Catholic folks can get to right up [Interstate] 279 to 79."

What O'Malley did for this weekend's eight semifinal games was get a list of 14 or 15 potential sites. He talked to athletic directors at those schools about their stadium's availability and then waited to see which semifinal matchup would fit best at which site. He then double-checked with athletic directors at site schools Monday morning to make sure everything was OK.

Surprisingly, some schools do not want to be sites for playoffs games. Also, it's difficult to conduct a playoff game at school that still has a team competing. Martorelli Stadium would have been a good neutral site for Hampton-Hopewell, but North Hills is still playing.

Members of the WPIAL football steering committee say their job is to set up the tournament field so that the top four seeds in each classification reach the semifinals. That rarely happens.

Look what happened this year. North Hills knocked off No. 4 seed North Allegheny in the semifinals in Class AAAA. Hampton upset No. 3 seed Chartiers Valley in Class AAA. Keystone Oaks defeated No. 2-seed Mount Pleasant and Greesnburg Central Catholic downed No. 3-seed Center in Class AA.

Class A is the only one in which all of the top four seeds -- No. 1 Rochester, No. 2 Laurel, No. 3 Clairton and No. 4 North Catholic made it to the semifinals.

Mike White's "High School Sports Edition" videos are featured exclusively on PG+, a members-only web site from the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.