Maybe Fernando Valenzuela doesn't understand English.

Seems as how the rookie lefthander and Dodger teammates Pedro Guerrero and Pepe Frias reportedly played in a two-game exhibition series in Mexicali and Tijuana, Mexico, during the weekend. Said Valenzuela's agent, Antonio De Marco: "He pitched three innings and did well? in a charity game in Tijuana. "It was my understanding that he did not get paid." Said Jerry Reuss, Dodger player rep: "I heard they were offered $3,000. One of our players called Marvin Miller to see if it was all right for them to go. Marvin told him not to . . . that playing would be a violation of the Uniform Players Contract, regardless of whether they are on strike." Said Al Campanis, Dodger general manager, initially: "I'm not going to comment because I just can't believe it happened". . .

But do Mel Allen and Art Shamsky understand Japanese? They're about to fill the void for New York pay cable viewers by doing satellited Tokyo Yomiuri Giants-Hiroshima Toyo Carp games Saturday and Monday. In English, or at least, said Allen, "the same language I generally use," and don't forget, Roy White plays for the Giants. . . Joining the Chicago White Sox, TV crew, when and if: Lou Brock. Relegating Jim Piersall to radio coverage. . .

Coming up on WDCA-TV-20 Saturday, 1 p.m.: Black College Tennis Classic, taped May 31, Kevin Belcher of Jackson State versus Remi Osha of Southern; half the advertising revenue and other support tagged for D.C. chapter, National Junior Tennis League. . .

Court to court: Dave Wilson, seeking extension of the injunction that kept the Big Ten from keeping him from quarterbacking Illinois -- but didn't save the Illini from conference sanctions -- is denied by the federal judge in Peoria. Little hope left of further college play, recordbreaking passer Wilson assembles a news conference in Chicago today; probably to inform the NFL he's available for supplemental draft, possibly to announce for Canadian ball. . . In Tucson, the prosecution has rested its case against Tony Mason, the former U. of Arizona football coach, after four days and eight witnesses.Now Mason's counsel attempts to beat those 15 felony counts involving alleged phony travel vouchers. . . In Atlanta federal court, seven Indy-car drivers have sued to overturn the 60-day suspensions imposed on them by Championship Auto Racing Teams for violating its ban and competing in rival USAC's Pocono 500 (rain-reduced to 305). Tom Sneva et al. want to race in Sunday's twin 125-milers at Atlanta International; the judge cleared them to practice, pending a hearing today. . . Ex-Packer Chester Marcol faces the next 80 nights in jail and undergo alcoholism treatment during two years probation by order of a Green Bay area court. He'd brandished a gun at his estranged wife in March. . .

The New York State Assembly has wrapped up a package of regulations to increase the safety of boxing -- ambulances and medical apparatus at all contests, new standards for prefight and postfight physicals, etc. -- headed for final approval within weeks. . . Now if the New England Patriots can persuade the Foxboro, Mass., Board of Selectmen to reconsider its refusal to license a Monday football game against Dallas at appointed ABC-TV time of 9 p.m., they can save the Sept. 21 game from a fate worse than Howard Cosell: a non-network starting time or perhaps removal to Giants Stadium. Foxboro citizens got sick and tired of rampant rowdyism during and after previous Monday nighters. . .

It's tough in the minors, too. American Football Association Commissioner Billy Kilmer hustled into Charlotte after the Carolina Charger players decided to quit after a week of protesting low pay and minimal fan support, but failing to win any guaranteed salary from owner Earl Todd. Mission accomplished, apparently: Kilmer emerged from a meeting with the team to say the players would resume practice and would play Shreveport as scheduled Saturday. Said Todd: "This meeting was by request of the commissioner. I didn't ask the team to come back and I don't intend to."