CSUN AT BAT: Cal State Northridge goes for a regional baseball title in Tempe, Ariz., this week. The Matadors, seeded second, open play in the six-team West Regional tournament Thursday against St. John's. The regional tourney also includes top-seeded Arizona State and defending NCAA champion Pepperdine. The winner advances to the College World Series. . . . Meanwhile, the Northridge women's softball team plays Southwest Louisiana Friday in that World Series at Oklahoma City (C6).