The best high school baseball players in the Pacific Northwest will square off against a team of all-stars from Southern California and Nevada in the inaugural Mariner Cup on Aug. 12-13 at Safeco Field.

Four players from the Western Conference South Division are on the Northwest team roster including pitcher Geoff Brown of Jackson, pitcher Owen Jones of Edmonds-Woodway and shortstop Pierce Rankin of Shorecrest. Catcher Kawika Emsley-Pai of Jackson made the team but will not play because of injury.

This will be only the second time high school players have played at Safeco Field. Safeco hosted the Class 3A and 4A Washington state high school baseball semifinals and finals in May.

The three-game series is the brainchild of Bob Fontaine, the Seattle Mariners’ vice president of scouting. Both teams will wear Mariners jerseys and play nine-inning and seven-inning contests on Saturday and a nine-inning game Sunday. Mariners’ scouts based in the Northwest will coach the Northwest team and Mariners’ scouts from Southern California will coach the Southern California squad.

The 26-player Mariner scout team is playing in the Cup this year instead of the Area Code Games in Long Beach, Calif.

Players from Washington, Oregon, Idaho and Utah in the classes of 2007 and 2008 tried out for the teams this past spring.

The players selected are “guys we feel have tools that would be attractive to professional baseball,” said Dana Papasedero, a Mariners area scout who will help coach the Northwest team. “They’re the best of the best.”

Scouts, agents and college recruiters are expected to pack the stands.

“I would be surprised if it was not attended by every major league team,” Papasedero said. “The Northwest has gained quite a reputation for producing good players now and the Southwest has always been a hotbed of baseball.”

The Northwest and Southern California teams have had a rivalry going for years, both in the Area Code Games and in fall baseball in Peoria, Ariz., Papasedero said.

In its eight years of existence, the Mariners’ Northwest scout team has produced 64 draft picks, including major leaguers Grady Sizemore of the Cleveland Indians and Jeremy Bonderman of the Detroit Tigers.

Plans are to expand the Cup next year to possibly include a group of Midwest all-stars sponsored by the Chicago White Sox and another Southern California team assembled by the Los Angeles Angels. The Mariners are the first major league team to try the Cup concept.

“We’re very excited about it,” Papasedero said. “It gives local kids the opportunity to play at Safeco.”

“It’s a very, very high caliber of baseball, the highest quality of players assembled in the Northwest in decades,” he said.

The action starts at noon Aug. 12 and 11 a.m. Aug. 13. Gates open at 8:30 a.m. Saturday and 7:30 a.m. Sunday. Cost is $5 for adults and children 12-and-under get in for free.