Fernando Valenzuela played catch for 25 minutes, the last eight off a mound, as part of the rehabilitation and reacclimation process for his ailing shoulder. Assistant trainer Charlie Strasser said Valenzuela continues to make progress, but there's no timetable regarding his possible return. . . . The contracts of minor league hitting instructor Tommy Davis, Vero Beach infield instructor Paul Popovich and San Antonio pitching coach Pat Zachry will not be renewed for 1989, the Dodgers announced. In addition, Bakersfield manager Gary LaRocque and San Antonio coach Mark Sheehy are being moved to the scouting staff. LaRocque will scout the Carolinas, and Sheehy will scout Northern California. . . . A survey of Pacific Coast League managers by the publication Baseball America placed four Dodger prospects among the league's top 10. Pitcher Ramon Martinez was No. 2, shortstop Juan Bell No. 3, pitcher William Brennan No. 5 and outfielder Mike Devereaux No. 7. San Diego catching prospect Sandy Alomar Jr. was No. 1.