Bill Walton joined the San Diego Clippers today at the highest salary ever paid an NBA player and said he expected the team to win the NBA championship with him next season.

Walton, 26, sat out last season with a broken foot and became a free agent. After word of his defection became known, the Portland Trail Blazers, who signed him out of UCLA in 1974, expressed shock at his departure to San Diego and said they expected "to be compensated accordingly for the most valuable player in the NBA."

Walton, 6-foot-11 and 225, known as a great rebounder and defensive man rather than a high scorer, was joined at the new conference by his wife Susan, their two children, his mother and father and his grandmother.

"It's indeed a pleasure to be here today on Mother's Day, back with my mother and my grandmother and my beautiful wife and my two boys," Walton said. "It's been a tough year for me but I'm extremely elated about signing with the San Diego Clippers and I plan to spend my entire career here.

I can't think of a nicer Mother's Day present. I not only visualize the Clippers winning this coming season, I expect it. A lot of pressure will be on me but I expect that. That's what sports is all about. On paper we're a great team but we will have to win it on the court."

San Diego club president Irving Levin and Coach Gene Shue beamed as Walton spoke.

Levin would not give a figure on Walton's salary on the seven-year contract he signed. A spokesman said, however, it was more than the $800,000 a year the Denver Nuggets pay David Thompson, the previous highest-paid player in the NBA.

Walton said his first goal was to bring the NBA championshiop to San Diego "and keep it here . . .

"San Diego is far and away the best place for me to play. My family is here, my home is here. Irving Levin is a great owner to be associated with and Gene Shue is a great coach. My foot is great. I have no problem with it."

Walton was on crutches for seven months after surgery to repair a broken bone in the arch of his left foot. He has been off crutches for 5 1/2 months, he said, and has been working out, playing basketball, at his home in Newport Beach.

"I know that I can continue to play the game that I love so much and to which I owe so much. It took me so long to make my decision because I wanted to make the right one. I predict a great future the Clippers. There are no limits to what we can achieve and I want to make them the most exciting club in the NBA. I foresee no problems with the Clipper players. I know I'll fit in." CAPTION: Picture, Bill Walton