The pro golf tour got its latest installment of bad news about the Walrus today as Craig Stadler, the first-round leader after a 66, shot a 69 to take a two-shot lead at the midpoint of the Doral-Eastern Open.

The sturdy blacksmith lookalike, whose nine-under-par total of 135 is two shots ahead of Andy Bean (69) and three ahead of Jack Nicklaus (71) and rabbit Mike Nicolette (70), chugged around Doral Country Club's Blue Monster ignoring one bit of aggravating misfortune after another.

For all the displeasure Stadler showed, he might as well have been cheerfully humming, "I Am The Walrus."

"I hung in and was patient," said Stadler, who has, traditionally, lacked only one golfing virtue--patience.

When Stadler bogeyed his par-5 opening hole of the day--taking four to get down from 70 yards away in the center of the fairway--the expectation was that he would self-destruct with a temper tantrum.

Instead, Stadler practiced the sort of newly learned self-control that has elevated him to the current No. 2 money winner on the TPA Tour.

"A couple of years ago, or maybe even last year, I probably wouldn't have gotten it in the fairway on the next hole," admitted Stadler. "But I took my time and just killed a drive, right down the middle."

Thereafter, his composure was impeccable as he made no more bogeys and four birdies on a tough, high-rough windy day. On his 16th hole of the day (the seventh), Stadler holed a 25-foot chip from the fringe, then closed his round with a flourish, sinking a 40-foot birdie putt on the final lazy turn of the ball.

"About five feet from the hole, I thought it was in easy. I started to get excited and, darn, the thing just barely got there," said Stadler, who until finishing eighth on the money list each of the last two years, was better known for his gruff than his golf.

Stadler, who has won four TPA events in seven years, including this season's Tucson Open, is known for his occasional streaky weeks when he seems unconscious and laps the field, as in his six-shot victory at the Kemper Open in Washington last year.

This week, Stadler seems to have only two serious opponents--Bean, who knocked his first shot of the day into a lake, yet battled to his 69, and the extremely determined Nicklaus, who holed a 98-yard pitching wedge shot for an eagle 2 on No. 5. But Nicklaus had the misfortune to play in the afternoon, when steadily increasing winds drove scores skyward.

Usually, after two rounds, the field still is bunched. Not this week. Two currently competent but hardly frightening fellows--Scott Hoch and Eric Batten--are tied at 139. However, to find big names behind Nicklaus, you have to look back to host pro Severiano Ballesteros, Jerry Pate, Tom Weiskopf and Wayne Levi at 140 and Ray Floyd, the champion the past two years, at 141.

The day's charmer was Nicolette, who could win more money this week than he has in his struggling four-year career (a meager $22,848). His 70 this morning included an amazing 12 one-putt greens and only 24 putts in all.

"I'm trying to stop thinking so much," said Nicolette. "Look at the ball, look at the flag and hit it. I've been making the game too hard." Rizzo Has 4-Shot Lead

TUCSON, Feb. 26 (AP)--Patti Rizzo shot a course record seven-under-par 65 today to take a four-stroke lead over Janet Coles after two rounds of the $125,000 LPGA Arizona Copper Classic.

The 21-year-old Rizzo, who turned pro last month, birdied five holes on the back nine of the 6,026-yard course--including the final three--for a two-round total of 136.

Coles shot another 70. Amy Alcott and Beverly Klass were tied for third at 141.