THE NFL DRAFT : Juniors Go to the Head of the Class : Pro football: Five of the first seven picks and eight in first round are underclassmen, but only 13 in first five rounds. USC’s Seau and Carrier go 5-6.

For 55 years, NFL teams have been drafting college people, with or without their permission. And in a span that long, a lot of strange things can happen.

But in some respects, Sunday’s critical opening phases of the 1990 draft--which ends with seven more rounds today--were the most unusual yet.

Consider all this:

--Linebacker Junior Seau and safety Mark Carrier, two USC juniors who decided not to play college football this fall, went fifth and sixth in the first round to, respectively, the San Diego Chargers and Chicago Bears.

--In the NFL’s first year of unrestricted drafting of underclassmen, five juniors were among the first seven players chosen. In all, eight were chosen in the first round, but only five more were selected in the next four rounds.

--The Raiders were good for a major early surprise when, drafting 11th, they took an Arizona pass-rusher, Anthony Smith, who missed a couple of late-season games with a knee injury. Smith spent two of his teen-age years in a drug rehab clinic. “Physically, one on one, nobody can beat me fighting because that’s what I grew up doing,” he told Steve Springer of The Times last fall. “I don’t enjoy the game as much as I like the hitting.”

--The Rams, facing a draft that was conspicuously weak in offensive linemen, drafted for need anyway, picking center Bern Brostek of Washington. Only one other offensive lineman--Richmond Webb of Texas A&M;, to Miami--was named in the first round.

--After top pick Jeff George was signed to a six-year, $15-million contract by the Indianapolis Colts, the team was panned in Indianapolis--the player’s hometown--and heavily criticized around the league for the trade that returned the Illinois junior quarterback to Indiana, his home state.

One problem, their critics said, is that the Colts gave the Atlanta Falcons too much: a Pro Bowl blocker, Chris Hinton, and a starting receiver, Andre Rison--the club’s first pick a year ago--plus a No. 1 next year. The other problem is that George isn’t that good, they said. In any case, he hasn’t proved it yet.

TROJAN PARTY

The quality athlete in this draft and the smartest, some scouts said, is Tiaina (Junior) Seau, who became Bobby Beathard’s first pick as San Diego’s general manager. In his Washington days, following George Allen’s lead, Beathard had usually traded his first choices for veteran players.

A Charger team that seems to be on the move in the AFC West will find a place to put Seau--who stands 6 feet 2 inches and weighs 240 pounds--despite his inexperience. “Experience will take place during mini-camp,” he said.

Carrier would settle for the same in Chicago. The Bears are owned by one of the league’s poorest but sharpest millionaire families, the McCaskeys, according to Coach Mike Ditka, who said they decided last week to draft a player they could sign.

Holding the day’s sixth choice, they wanted, Ditka said, a good, useful player if not necessarily sixth-choice quality. The key was his willingness to sign.

And that’s how Carrier became a Bear. He agreed to a five-year contract.

“I’m quicker than people think,” he said.

YEAR OF THE JUNIOR

In addition to George, Seau and Carrier, the underclassmen picked in the top seven were Alabama linebacker Keith McCants and Houston quarterback Andre Ware, who were drafted by, respectively, the Tampa Bay Buccaneers and Detroit Lions.

McCants, 6-4, 258, projected as the top pick not long ago, was singled out in an Atlanta newspaper Sunday as a player with a knee problem.

“It’s mind-boggling that (the newspaper) came up with that on the day of the draft,” McCants protested.

The Buccaneers, who drafted him fourth, confirmed that the knee problem is minor. Fortunately for McCants, Ray Perkins, the leader of the Buccaneers, is the coach who three years ago recruited him for Alabama.

Detroit, meanwhile, is still loading up on Heisman Trophy winners--running back Barry Sanders last April and quarterback Ware this time.

Ware, 6-2, 210, is moving from one run-and-shoot team to another. But in Detroit, assistant coach Mouse Davis, the creator of that offense, said Ware isn’t just a run-and-shoot quarterback. “He’s a quarterback, period,” Davis said. “He can do it all.”

In the opinion of Lion scouts, Rodney Peete will become a backup quarterback. “The best backup in the league,” one said.

ROLE MODEL

It was Barry Sanders whose success last season at Detroit, as a junior product from Oklahoma State, helped spur 38 juniors to apply for Sunday’s draft. And as the day wore on, it was clear that he is still influencing the thinking of pro scouts.

Though Sanders weighs 200 pounds, he stands only 5-8. And of the six running backs in Sunday’s first round, none is over 6 feet. Several, in fact, could bookend Sanders, who attributes his agility in part to his short stature.

The first running back to go, and the second player drafted, was Blair Thomas of Penn State, who became Dick Steinberg’s first choice as the general manager of the New York Jets. Thomas became the 72nd Penn State player drafted into the NFL since 1970.

The Dallas Cowboys traded up--making their 15th trade in six months--for Florida halfback Emmitt Smith, 5-9, 200, who, presumably, will now give Coach Jimmy Johnson and quarterback Troy Aikman a running game.

The Falcons lost their first pick in the George deal but gained the best pass receiver among the running backs, Los Angeles native Steve Broussard of Washington, who stands 5-6 1/4 and weighs 200. Broussard was the 20th player drafted.

DEFENSIVE THINKING

The high-priced first round was basically a defensive round. There were 13 defensive players among the first 18 picks--seven of them linebackers.

One highly regarded linebacker, Chris Singleton, one of two Arizona players in the first 11 picks, went to the New England Patriots shortly before Smith went to the Raiders.

Linebacker Lamar Lathon, a teammate of Ware at Houston, moved across town to the Oilers, where he rejoined the coach he and Ware had played for in college, Jack Pardee.

One reason for the emphasis on defense was the lack of pass-catching quality at the top of the draft. No wide receivers were taken in the first round. And there was only one tight end, Eric Green of Liberty, a Division I-AA school in Virginia.

Green, 6-4, 265, drafted 21st by the Pittsburgh Steelers, didn’t have much competition at Liberty, whose football opponents include Eastern Illinois, Eastern Michigan, Central Florida and Kutztown.

But he was well-coached at Liberty. The Flames are led by Sam Rutigliano, former Cleveland Browns coach.

TOP TRADE

If the Colts made the day’s worst trade, the Seattle Seahawks, conceivably, made the best, trading up for Miami defensive tackle Cortez Kennedy, 6-1 3/8, 290 or 300.

Some scouts called Kennedy the only substantial draft choice in the first six or seven picks--the only proven player. The others were all either inexperienced juniors or, in the case of Thomas, a player coming back from a knee injury that cost him one full college season.

Seattle Coach Chuck Knox, who went in with the eighth and 10th picks in the first round, yielded them both to New England for Kennedy’s rights.

ALL-STARS

Because most of the leading underclassmen are in this year’s draft, the 1989 Absolute All-American lineup is as close to the last word as NFL scouts can make it. Here is the All-American team with the top-drafted players at each position:

Offense: WR Alexander Wright (26) Auburn, Cowboys; WR Reggie Rembert (28) West Virginia, Jets; TE Eric Green (21) Liberty, Steelers; OL Richmond Webb (9) Texas A&M;, Dolphins; OL Bern Brostek (23) Washington, Rams; OL Keith Sims (39) Iowa State, Dolphins; OL Tim Grunhard (40) Notre Dame, Chiefs; OL Leo Goeas (60) Hawaii, Chargers; QB Jeff George (1) Illinois, Colts; RB Blair Thomas (2) Penn Atate, Jets; RB Emmitt Smith (17) Florida, Cowboys.

Defense: DL Cortez Kennedy (3) Miami, Seahawks; DL Ray Agnew (10) North Carolina State, Patriots; DL Anthony Smith (11) Arizona, Raiders; DL Reynaldo Turnbull (14) West Virginia, Saints; LB Keith McCants (4) Alabama, Buccaneers; LB Junior Seau (5) USC, Chargers; LB Chris Singleton (8) Arizona, Patriots; LB James Francis (12) Baylor, Bengals; DB Mark Carrier (6) USC, Bears; DB James Williams (16) Fresno State, Bills; DB Ben Smith (22) Georgia, Eagles; DB Robert Blacknon (34) Baylor, Seahawks.

* THE FIRST 5 ROUNDS: C16