Tommy Prothro, who had high hopes for the San Diego Chargers this season, resigned as the National Football League team's head coach yesterday after former St. Louis Cardinal Coach Don Coryell.

"Last winter I told (Charger owner) Gene Kleim I would coach only one more year because I felt we had a good team and would have a good year," said the 58-year-old Prothro in announcing his resignation. "I still believe this is a good football team and it is a playoff contender.

"However, after disappointing losses to Oakland and Denver and the disaster against Green Bay, I feel a fresh approach and a rude awakening may be what this team needs."

Prothro referred to the 24-3 setback the heavily favored Chargers suffered to the Packers at San Diego Stadium Sunday.

"I certainly hope this team will not think I am quitting on it or have lost confidence in the players," added Prothro, who was in his fifth year as the Charger coach. "I take this action only because I want it to be for the best interest of the team."

Coryell coached the Cardinals from 1973-77, compiling a 42-27-1 record and guiding them to the playoffs three times. He was not rehired after the 1977 season season when the team lost its final four games to finish 7-7 and Coryell criticized team owner Bill Bidwill.

The Cardinals' action came after Coryell flew to Los Angeles to discuss the possibility of coaching the Rams. Because Coryell had two years remaining on his St. Louis contract, the Chargers have agreed to give St. Louis their third-round draft choice in 1980.

Klein has offered Prothro an opentitled position with the team to work in personnel areas such as drafting, trading and player selection.

"I may follow this course," said Prothro. "But before deciding I want a while to consider what I want to do with my future. I am also interested in doing some traveling and playing alot of bridge."

Prothro said his wife Shirley, "was very relieved with the decision."

Prothro's record with the Chargers was 21-39. Before coming to San Diego, he was the head coach at Oregon State for 10 seasons starting in 1955, head coach at UCLA from 1965-70 and the Los Angeles Rams' head coach in 1971-72. He sat out the 1973 season.

"This was a very difficult thing for me," said Klein."I like and respect Tommy greatly and hope that he stays with the organization in a personnel position."

Coryell was the head coach at San Diego State from 1961 to 1972 before going to the Cardinals. His San Diego State teams compiled a 104-19-2 record.

"I certainly hope I'm worth it," said the 53-year-old Coryell of the third round draft pick. "I'm pleased with the opportunity to coach again in San Diego because it's like a dream come true."

It had been rumored for months that Coryell would succeed Prothro as head coach. Terms of his agreement with the team were not divulged.

"I thought I could take the year off without coaching football but I started to get itchy when I attended a Dallas San Diego rookie scrimmage in Irvine," Coryell said. "I haven't seen the Chargers play this season except on television, but with a few breaks the team could be 4-0."

Coryell said he plans to keep the staff of assistant coaches and noted that the overall philosophy of the Chargers, offensively and defensively is very close to his own.

San Diego was 7-7 last year and hopes were hish going into this season. The Chargers won their opeining at Seattle, 24-20, and led Oakland most of the way in their second game. But a controversial fumble recovered by the Raiders for a touchdown on the game's final play gave Oakland a 21-20 victory.

In their third game at Denver the Chargers held a 14-13 lead with less than four minutes remaining when Rick Upchurch returned a punt 75 yards for a touchdown and the Broncos eventually won, 27-14.

On Sunday, despite a team-record 10 quarterback sacks, the Chargers committed 11 turnovers in losing to the Packers, Prothro said he stayed at San Diego Stadium until almost midnight looking at game films, and it was during that time he decided to resign.