The Washington Bullets placed guard Steve Colter on waivers last night, just a week after acquiring him as a replacement for the injured Darrell Walker and two days after Coach Kevin Loughery suggested he might become a starter in the team's lineup.

Loughery could not be reached for comment about the move, but it was clear that the Bullets were taking a gamble. Had Colter remained with the team after 6 p.m. yesterday, Washington would have been required to pay him for a full season. The minimum NBA salary is $75,000.

By waiving him when they did, the Bullets could recall Colter and sign him to two separate 10-day contracts before having to make a decision on whether to keep him all season. The gamble is that another team could sign Colter first.

The Bullets may need some help. Jay Murphy underwent a CAT scan yesterday that revealed that a herniated disk is to blame for his sore lower back. He will be out eight to 10 days, the team said.

Even if the Bullets decide to re-sign Colter, he'll miss tonight's game against the Portland Trail Blazers at Capital Centre, because any players placed on waivers can't be re-signed before Thursday. Earlier yesterday, Loughery said that, for tonight at least, Frank Johnson would remain the team's starting point guard.

After practice at Bowie State College, Loughery met with Johnson. After a 102-97 loss at Milwaukee Saturday, Loughery said the team's point guards, Johnson and rookie Tyrone Bogues, hadn't been playing up to par. Loughery said yesterday's talk "was just to make sure that everything was all right" with Johnson.

"He told me that I wasn't playing the same way that I've played in the past," Johnson said. "However, how I think I'm playing isn't as important as what he thinks. I'm not in the business of evaluation, that's up to Kevin and {Bullets assistant coaches} Bill Blair and Wes Unseld. Whenever I'm out there, I'm going to play hard."

One of the things that might be most beneficial to the Bullets is out of their hands: the discretion of the league's officials. A number of people in the Bullets organization say privately that they believe center Moses Malone is no longer getting the same number of foul calls and, consequently, free throw attempts.

"When he's inside, it used to be that when he got hammered he'd get the call, say, seven out of every 10 times. Now, it's only three or four times," said one team official.

Malone has said all season that he believes he doesn't get calls from officials when an opposing coach has complained about the number of trips Malone takes to the line. In the opening game of the season, he hit 20 of 23 free throws against Atlanta; in the fourth game of the season, Malone was 18 of 21 in a 108-102 win over New York.

Following that game, Knicks Coach Rick Pitino called Malone "the greatest actor since Paul Newman." In the 20 games since the Nov. 13 contest against New York, only once has Malone shot at least 15 free throws. In Washington's 109-96 victory over the Chicago Bulls on Dec. 19, Malone didn't shoot one.

That was unheard of for a player who has shot a minimum of 690 free throws for each of the last nine seasons. Although Malone hit a career-high 82 percent, his 692 attempts from the line last season marked the first time since 1978 that he shot fewer than 700 free throws.

At his current pace, Malone would end the 1987-88 season with approximately the same number of attempts as last season. That's one reason why Rod Thorn, the NBA's vice president of operations, said the idea of league officials trying to curtail Malone's free throws is ridiculous.

"It certainly hasn't been said by anyone here and it never would be," Thorn said. "Obviously he's not getting to the line as much as he's done before, but I don't think the refs are reffing him differently . . . Is he taking as many shots as he has in the past? Is he handling the ball as much? I just don't think he's getting fouled as much."

"He's never taken a lot of shots from the field because he went to the line so much," retorted Blair.

Malone's absence from the line has hurt the team. If the center isn't getting the calls, it takes away what's usually the first option of any team's offense -- getting the ball into the low post -- and forces Washington to use a more perimeter-oriented style.

Such a style leads to fewer fouls called overall. "We need Moses to pick up those foul calls because it gets us into the bonus that much quicker," said Johnson. "When that happens, the other people's big men get in foul trouble and they can't play us as aggressively."