For a candidate with only token opposition for his party's nomination for Virginia attorney general, Republican state Del. W.R. (Buster) O'Brien seems to be encountering a lot of problems.

First, there was the snafu over his professional football career. Did he or didn't he play ball for the Washington Redskins, the San Francisco 49ers and the Ottawa Roughriders? Yes, said his official biography. Well, sort of, said football spokesmen who noted that the Virginia Beach legislator tried out for two of the teams and was on the reserve squad of the third.

Then there was the recent Virginia television show during which political analyst Larry J. Sabato labeled O'Brien, 38, "one of the laziest statewide candidates" he'd ever seen.

And now, J. Smith Ferebee of Richmond, a leading GOP fund-raiser, has joined in criticizing O'Brien for not working hard enough in his campaign for the third spot on the Republican ticket.

"I don't know where he Sabato got that," O'Brien shot back yesterday. "I haven't been home since the first of February. I've been going to meetings, and Republican picnics and teas all over the state."

O'Brien, a legislator since 1980, said he plans to shut down his law practice next week to devote all of his time to the campaign.

Less than two weeks before the state GOP nominating convention in Norfolk, O'Brien disclosed that he has changed campaign managers. Jeff Gregson, fresh off the defunct gubernatorial campaign of Republican Rep. Stan Parris, replaced Bob (Buzz) Buzinski on Monday. O'Brien said Buzinski left the campaign to take a permanent job with the federal government in Washington.

Does the switch at the top of the campaign so close to the nominating convention signal internal problems?

"No, not at all," said O'Brien.

"I haven't found any real troubles in the campaign," said Gregson, who said he plans to remain on O'Brien's staff only through the state GOP convention May 31-June 1.

Gregson said he was "disgusted" by Sabato's television comment. "I don't see where he would have the factual basis," said Gregson. "It happens that O'Brien is one of the most energetic candidates I have ever worked with."

O'Brien's only opponent for the Republican nomination is a little known Richmond attorney, Winston Mathews, whose primary campaign platform centers around his pledge to remove the controversial game "Dungeons and Dragons" from the state's public schools.

Del. Mary Sue Terry of Patrick County is the only candidate seeking the Democratic nomination for the job.

Asked to assess the aggressiveness of the O'Brien campaign, Terry's spokesman John Jameson said: "It hasn't been what I would describe as a competitive campaign yet. There have not been a lot of situations that lend themselves to competitiveness."

Both candidates said they have concentrated their efforts on wooing support from their own party leaders as opposed to launching attacks on the competing party.

O'Brien added that he is "looking for somebody right now" to run his campaign after the nominating convention.