HERSHEY -- When Selinsgrove and Archbishop Wood walk on to the field at HersheyPark Stadium at 7 tonight in the PIAA Class AAA semifinals, it will be the first time either school has made it this far in the football playoffs.

For the Seals, the road to the state title has hit a speed bump in the quarterfinals over the last four years in the form of the WPIAL champion.

For the Vikings, this is the first season the Philadelphia Catholic League football champions have been eligible for the state football playoffs.

The teams have several other things in common. They both lost their first game of the season, the Seals to Mount Carmel, while the Vikings dropped an overtime game to Pennridge. But maybe the biggest commonality is that they don't know a whole heck of a lot about each other, either. Neither has played a common opponent this season.

But it's not the things that make them alike that will determine a winner between 13-1 Selinsgrove and 10-2 Archbishop Wood, but their one big difference.

Size.

"This is physically the biggest team we will face all year," Selinsgrove coach Dave Hess said. "The challenge is going to be to control the line of scrimmage with all that size."

The winner of the game tonight will play in the state final back at HersheyPark at 7 p.m. next Friday against either Thomas Jefferson (13-1) or West York (13-1).

The Vikings' size advantage up front begins with 6-foot-5, 326-pound tackle Adam Citko, a senior already committed to Temple, but they also have three offensive linemen over 250 pounds.

Add to the fact that the big line is blocking for a big tailback in 6-foot, 200-pound senior Sean Cunningham. Cunningham has rushed for 1,673 yards and 26 touchdowns this season, but has been almost unstoppable the last four weeks, rolling up 695 yards and 13 touchdowns over the last month. Cunningham holds the school-record for rushing yards in a season, breaking Bryan McCarthy's record set in 2004. Bryan McCarthy is the older brother of current quarterback Sean McCarthy. Cunningham has earned some Division 1-AA looks this season for football, but also has a partial lacrosse scholarship to Drexel.

Sean McCarthy, a 6-foot-3, 170-pound senior, is a dangerous run-pass threat. McCarthy is second on the team in rushing with 536 yards and 11 touchdowns. McCarthy is 68-of-117 for 1,147 yards and seven touchdowns.

"The running back is a real talent," Hess said. "They run a multiple-I formation, but they'll spread it out as well."

Archbishop Wood head coach Steve Devlin is 20-5 in two seasons at the school after eight years as an offensive coordinator at St. Joseph's Prep, one of the top football schools in the country.

On the defensive side of the ball, the Vikings also use their size to their advantage. Citko doesn't start on defense, but plays in the defensive tackle rotation, which has become more prevalent the deeper Archbishop Wood has made it into the playoffs.

"They play a straight 4-4 like we used to," Hess said. "They are massive up front. It's going to be a challenge."