It was a strange turnabout from baseball's earlier pattern of contributions toward racial equality. A team from Philadelphia had to convince the Dodgers to postpone their opener out of respect for the murdered Dr. Martin Luther King Jr. and thus make the decision unanimous among major league owners. When all the clubs finally did open up on Wednesday last week the absence of some players and thousands of fans from ball parks plainly marked the beginning of an unsettling season ahead. In the violent aftermath of Dr. King's death player-soldiers, who had been worried about Vietnam, were suddenly tapped for local guard duty. One was Baltimore's shortstop, Mark Belanger, who is considered so good that the Orioles traded Luis Aparicio. Now Manager Hank Bauer has neither. Others were missing from the Baltimore, Detroit and Washington rosters, including Senator Infielder Ed Brinkman (right), who ended up patrolling in D.C. Stadium, where he had been scheduled to start at shortstop. At the same park, 10,000 ticketholders failed to show up for the opener and only 7,700 made it to Chicago's Comiskey Park the same day. Fans' fear of traveling out to the park is one factor giving the season a look of instability greater than any since World War II, when a manager never knew what uniform his catcher would be in at the All-Star break and a 15-year-old pitched for Cincinnati. But the threat of new call-ups is more worrisome. Some teams already are aware that 40% of their players must perform military duties this summer. Further demands could alter rosters with each reveille and make shambles of the pennant races. Remember the St. Louis Browns of 1944?