CHICAGO, JULY 9 -- Guesswork is not required if you're trying to figure out what the Washington Commandos have been practicing this week. After all, it isn't often that a football team has an opponent score 73 points.

Yes, it's defense time for the Commandos, who will face the Chicago Bruisers in Arena Football at the Rosemont Horizon Friday night, and Coach Bob Harrison isn't slow to point out the problems his team had last week in its 73-57 loss to the Denver Dynamite. New Denver quarterback Whitt Taylor threw for 10 touchdowns, completing 27 of 35 passes for 399 yards on the 50-yard-long indoor field.

Although Harrison primarily credited Taylor's quick release and scrambling ability after last week's game, he said today that "we were making mistakes that allowed him to have that type of game."

What started problems for the Commandos, Harrison said, was the season-ending knee injury that running back/defensive back Richard DuPree suffered the week before against Denver at Capital Centre. DuPree was a consistent two-way player (a limited number of replacements allows for some one-way players), and his loss prompted a series of changes in the defensive backfield.

His spot at safety was filled by Frederick (Rex) Motes, who normally plays cornerback. While Nathan Creer started in his usual cornerback spot, Dwayne Dixon and Lenny Taylor alternated at the other corner. Neither Dixon nor Taylor specializes at cornerback, and assistant coach Jim Williams said a clear problem arose because, at any time, there were two players in the backfield who weren't used to their positions.

"It was totally a situation of inexperience, particularly when it came to those guys working together," Williams said. "If two receivers cross, one defensive back has to be saying to the other that he will take a certain guy if he goes inside and that he'll take the other if he goes outside. You have to do those kinds of things."

Creer said the main problem was that, on any given play, one part of the defense would make a mistake. "If it wasn't the defensive backs making a mistake, it was the linebackers or the linemen," he said. "We just went back to basics this week and we've been working together.

This week, Dixon will play safety, and Creer and Motes will cover the corners. Harrison said he will substitute more to prevent fatigue.

In case anyone wonders why there was no roster substitute for DuPree that would have solved the problem, well, there was. Sort of.

Running back/defensive back David Groman was brought in last week, and was released a week later. The new man now is Steve Griffin, a 6-foot, 185-pound receiver from Purdue. He hasn't played defense since high school, but Harrison said he has been working at both offense and defense. Harrison added that Griffin won't start but will play.

But if the Commandos' roster moves seem complicated, they're nothing compared to those of the injury-riddled Bruisers. Chicago Coach Ray Jauch, the former Washington Federals coach, has brought in six replacements so far. One came when the team's backup quarterback, Sean Payton, left for the Canadian Football league. Of course, in Arena Football, six players means more than one-quarter of a roster.

Before the season started, league officials constantly stressed how they wanted equal teams, but the Bruisers are evidence that the plan didn't completely work. Jauch took several players with injury-filled pasts, and many hurt themselves again.

"I think the idea was right," he said. "It's just unfortunate it didn't work out for us. There's no foolproof way to make all things equal. These guys are playing hard and working hard. I wish for their sake that they could win a game or two."

Chicago's biggest question is Reggie Smith. A 5-6, 170-pounder, he prefers the nickname "Supergnat." He pulled a hamstring in Chicago's second game. He is the primary key to the long passing game and will probably play Friday.

Jauch said he will start quarterback Mike Hold, but added that Payton's replacement, Kevin Williams, might play after only a few days of practice. "Mike has not had the type of year that I think he can have," Jauch said.