Joe Thomas, the irasible architect of championship football teams, is expected to leave the Baltimore Colts to become general manager of the flounduring Atlanta Falcons.

The anticipated move, which could come as soon as next weak, will stamp Ted Marchibroda, the Colt head coach, as the winner in his power struggle with Thomas.

Saying goodbye to Baltimore is not something Thomas wants to do, even though he presented team owner Robert Irsay with a seemingly impossible contract demands for him to stay on as general manager - $350,000 a year for five years and absolute power over the organization.

Thomas' reasons for wanting to stay are that he is 55, he has had open-heart surgery, and he has built two National Football League power houses - Minnesota and Miami - without remaining to enjoy the fruits of his labors.

But with Marchibroda, a quiet man but not a man without a strong will, apparently gaining more and more clout with Irsay, sources say that Thomas apparently seems himself as having no other choice.

The shift from the Colts, American Conference champions for the second straight season, to the 4-10 Falcons will not, however, be without financial rewards far beyond the $125,000 to $150,000 Thomas is reportedly earning in Baltimore.

It is believed that Thomas would have preferred to move to New York. But the Giants, loaded with members of the Mara family and with old players, weren't about to give him free rein, and neither were the Jets now that they are under a tough interim president named Leon Hess. That left Atlanta.

At least that is what sources say. Rankin M. Smith, the Falcons' chairman of the board, insists that he and Thomas, have not discussed money.

Indeed, Smith said yesterday. "I haven't even offered Joe Thomas the job. I plan to see him in California at the Super Bowl. I plan to see a lot of other people. He is not the first man I've talked to. He is not the last man I'm going to talk to."

Smith, a millionaire insurance man, also put himself on the record as being against paying a general manager who can't pass, punt or kick $350,000 "or even $300,000, for that matter."

"If Joe Thomas can get that somewhere else," said Smith, "he better go. If he can get me the job. I might even go."

Nevertheless, people around the NFL expect Smith to come up with big money for Thomas and they expect Thomas' asking price to come down after the news that Marchibroda and Irsay met in Chicago this week.

They were discussing a new contract for Marchibroada, who never signed one in September after resigning because of Thomas' interference and then rejoining the Colts three days later to the halleluljahs of his players.

"It was just a preliminary meeting," Marchibroada, a former Redskin assistant coach, said yesterday. "Working out a contract takes a little time.

It's king of hard not to, considering the situation. I'd really rather not say any more about it than that."

Marchibroda, who has total control of the football operation, said he is not interested in taking on double duty as a coach and general manager "at the present time." Sources confirmed that, adding that he would only assuem Thomas' position if he had no other choice.

The most likely development in Baltimore, the sources went on to say, is that the next general manager will be a man Marchibroda can get along with.

Candidates for the job at the moment include Johnny Unitas, the legendary Colt quarterback who was forced out of town by Thomas; Ernie Accorsi, a former team publicist who is now an assistant to the president of the American conference, and Dick Syzmanski, who blossomed from a Colt player into the team's director of pro personnel.

Contacted in California, Accorsi said only that he has heard his name mentioned "and I don't have anything to say other than that."

Unitas and Syzmanski could not be reached for comment, nor could Irsay, who once coveted Thomas and now is willing to let him dicker with other teams, although there is a year left on his contract.

The most startling fact in the Baltimore scenario is that Thomas had to beg Irsay to give Marchibroda a crack at the head coaching job in 1975.

It was a big gamble for Thomas, who had hired nothing but duds for the Colts previously and had even muddled through half a season of calling the shots himself. But finally he convinced Irsay, the star-struck air-conditioning magnate, that Hank Stram was not what the Colts needed - Marchibroda was.

Thomas admired Marchibroda for his full-blooded offense. Marchiborda admired Thomas for his track record. It was a beautiful marriage until the Colt's turned their 4-10 record of 1974 into 10-4 and the conference title.

Then praise rained down on Marchibroda from every city where there was a football fan and, insiders say, Thomas boiled over with jealousy. Another man was getting credit for what he had done.

What Thomas failed to realize - or didn't want to realize - was that Marchidroda had gotten as much as was humanly possible out of the talent given him. He had created an atmosphere in which th players who didn't worship him, the way Bert Jones does, it least respected him.

So the bickring between th two men started, and by the end of the Colt's last preseason game, it exploded into Marchibroda's resignation and subsequent rehiring.

Marchibroda and Thomas spent the next six months trying to be as civil as possible to each other in public. But privately they were alwasy digging at each other.

When the Colts' organization hosted a dinner for Howard Cosell before a Monday night TV game, Irsay had to force Thomas to invite Marchibroda. The sligtly-built coach did not wait long to get back at Thomas. When he was asked to speak at the dinner, Marchibroda looked at Thomas and said, "With me, it's always thrith-and-eight around here."

Thomas could live with that. He could not live with what Marchibroda said after Pittsburgh beat the Colts, 40-14, in the American conference playoffs. "Evidently we don't have a team with Supr Bowl talent," Marchibroda said. Thomas, the builder of champions, then went storming to Irsay to ask permission to go job hunting.

IN essence, Thomas was giving Irsay a choice. He was telling the owner he could have a man who is a genium at judging talent or he could have a coach whose departure would mean the dissolution of a team. But he could not have both.

In fact, Thomas was giving Irsay no choice at all.