Lakers Prepared for an Eye-Opener : Basketball: Still adjusting to changes, they start the season with a tall test at San Antonio.

The proprietors of Showtime are lashing down the circus tents for heavy weather.

The Lakers will open their season and Mike Dunleavy’s career as a head coach today against the Spurs with more worries than David Robinson and a Hemisfair full of screeching Texans.

With a new coach, a new starting center, two other new players in the rotation and a system they still don’t have down, the nine-time defending Pacific Division champions face unusual uncertainty.

The only question used to be: How to best stay interested till the finals?

“We’d go in, we knew what we were going to do,” Magic Johnson says. “We’d look at that first 20 games and we already knew --and basically it was right to detail.

“We’d look at 20 games and say, ‘We want to be 17-3.’ ”

Don’t laugh, that’s what they decided they wanted to do last season--and settled for 15-5.

This season’s early schedule?

“Yeah, I looked at it,” Johnson said. “This year, it’s more us getting our team together than saying, ‘Da-da-da-da-da.’

“It’s all new now. We’ll see what happens. I think it’s going to take 10 games to see where we’re at. And then we’ll go from there to set goals.”

You can find the Lakers’ cause for optimism in a hurry:

They’re still the Lakers.

Or as Phoenix Coach Cotton Fitzsimmons said:

“Have you checked the obituaries? I haven’t seen Magic’s name in there. I haven’t seen (James) Worthy’s name in there. Until you do, they’re still the team to beat.”

But the final three exhibitions had a decided un-Laker feel: a 30-point loss to the Golden State Warriors, followed by victories over the overmatched New Jersey Nets in which the Lakers scored only 103 and 94 points. They shot 43% and, apart from James Worthy, no starter shot 44%.

Dunleavy said he hadn’t been able to install everything he had intended. “There are a lot of changes and some of them, I guess, are going to be slow in coming,” he said.

General Manager Jerry West acknowledged concern, saying, “At this point in time, we have a lot of catching up to do.”

Everything is a puzzle. West seems once more, against all odds, to have upgraded the roster. But everyone else in the West did, too, so was it enough?

Sam Perkins, signed at a no-bargain free-agent price of $19.2 million over six seasons, gives the Lakers a quality, if unspectacular, big man who can play all along the front line. He’s an improvement over the flashier Orlando Woolridge, even if the souped-up Denver Nugget offense lands Woolridge among the top 10 scorers.

Terry Teagle takes the place of Michael Cooper. If no one can match Cooper’s kind of intangibles, Teagle brings, in Johnson’s words, “scoring at that spot that we haven’t ever had here.”

If there is concern about a player, it falls on the bearded and celebrated head of Vlade Divac.

After his intriguing rookie season, West made him No. 1 at the start of the summer. But the Lakers haven’t liked what they have seen since.

Originally projected as a big forward, it’s an open question anyway whether he can play defensive center. Divac’s promotion may be cosmetic. Mychal Thompson played more minutes than Divac through the first seven exhibitions and Dunleavy has Perkins warmed up to relieve there, too.

The rest of the cast you know:

James Worthy--Shot 55% in exhibitions, ready to prove his playoff slump against Phoenix was an aberration.

Byron Scott--Psyched and feeling sound, he looks capable of rebounding from his two-season slide.

A.C. Green--The working man’s Laker and still the starter but Perkins will push him.

Mychal Thompson--Brains and muscle still make him useful at 35, although the Lakers aren’t keen to expose him full-time to big, young opponents.

Larry Drew--Faded away last season, grew unhappy with Pat Riley as his minutes varied. Looking better now.

Elden Campbell--At 6-11, the last pick on the first round, he looked like a coup but spent the exhibition season in foul trouble. He’ll have an uphill battle for playing time but has raw talent.

Magic Johnson--Enough said.

Laker Notes

In his own debut, former coach Pat Riley will be co-host of the NBC telecast from New York. Says Riley: “I don’t think you can really judge the Lakers in preseason. Those guys are going to play together, the five-six who’ve been there. And I think the new guys will fit right in. As soon as they get really comfortable with what Mike (Dunleavy) wants, I don’t think they’ll be anything but a great team.” . . . Magic Johnson on opening here: “It’s exciting. It’s fun. Why not? That’s what it’s all about. Let’s go somewhere where it’s wild and crazy. Hey this is the team (Spurs) that’s supposed to win the West--so let’s go up and see.”