Maryland Gov. Robert L. Ehrlich Jr. has agreed to limit the potential number of sites for slot machines, eliminating one obstacle to their legalization in the state but also possibly putting Pimlico Race Course in peril. Ehrlich's concession to House Speaker Michael E. Busch, who had insisted on the limit, could mean that Pimlico would end up without slots, if the machines are authorized in Maryland.Busch had insisted slots licenses be limited to one per company. Since the Maryland Jockey Club and its parent company, Magna Entertainment Corp., own both Pimlico and Laurel Park, that would mean they could install slots at only one track. Laurel, which is closer to Washington, D.C., would presumably be the more lucrative site. MJC officials have said if Pimlico doesn't get slots and nearby sites do, then the historic track might have to wait indefinitely for needed remodeling or even close. Ehrlich also has agreed to permit slots at sites other than racetracks. He had proposed initially they be limited to tracks. Now, he says he would support the machines at one or more tracks and one or more free-standing emporiums. That is another concession to Busch, who almost single-handedly blocked approval of slots in the General Assembly early this year. Paul Micucci, executive vice president of gaming for Magna, said limits on slots based on ownership were unfair. "To unfairly penalize any facility simply because of shared ownership puts at risk the economic viability of the facility left behind," Micucci was quoted as saying in the Baltimore Sun. "Presumably, there would be no issue if Pimlico and Laurel had two owners. Why should the owners of the Maryland Jockey Club be penalized for making a large investment, rather than a smaller investment, in an important Maryland industry?" The General Assembly will take up the debate on slots when it convenes in January. There has been some talk of a short special session before than to deal with the issue, but that appears to be no better than a 50-50 proposition, said Paul Schurick, the governor's chief negotiator on slots.