LAKE FOREST, Ill. —When a team wins five straight divisional championships with a dominating defense and then slips to a 6-10 season as the defense takes a dive, it isn’t difficult to determine what the Chicago Bears need in the upcoming draft.

The Bears were No. 1 in defense for four straight years and then slipped to No. 2 in 1988 when they won their fifth straight divisional title. Last year they dropped all the way to 25th in league rankings.

The Bears have the sixth pick in the draft and there is no question that the choice will be a defensive lineman. They also have two more choices in the second round and two more in the third or five of the first 64 players to be selected.

That’s pretty heady considering a number of juniors have opted for the draft, making it stronger than usual. In addition to No. 6, the Bears will have the 32nd, 33rd, 61st and 64th players.

Last year they won their first four games and looked like a team headed for great heights. Then tackle Dan Hampton went down with a knee injury and the Bears won only two of their last 12 games. Hampton is 33 and will attempt another comeback on knees that have undergone surgery 11 times.

Steve McMichael, the other defensive tackle, is 32 and unhappy with his contract. Then there’s William Perry. Ditka has served another ultimatum that Perry come to mini-camp in May under 320 pounds.

Age and weight aren’t the only problems up front. Behind defensive ends Richard Dent and Trace Armstrong, there is little depth because of players lost through Plan B free agency. Backup help is needed at defensive end.

Ditka, who claims the team has to restore its confidence and regain a winning attitude, is counting heavily on Hampton, McMichael and Perry.

The top defensive linemen in the draft are Cortez Kennedy of Miami; Marc Spindler of Pittsburgh; Dennis Brown of Washington; and Craig Veasey of Houston.

Bill Tobin, director of player personnel, is the man who calls the shots in the draft along with input from Ditka and the scouts.

The Bears’ first three selections will probably be defensive players. When they get to the third round, they might address some problems on offense. With Matt Suhey having retired and Brad Muster coming back from back surgery, fullback could be a priority.

After the first three rounds, the Bears will have a single pick in each of the subsequent nine rounds.

Other needs will be met in those rounds. With Thomas Sanders going Plan B, the Bears could use a running back. They also are expected to pick a quarterback down the line to back up Mike Tomczak and Jim Harbaugh.

Ditka insists the Bears can win with Tomczak and Harbaugh provided the rest of the team does its job.