Defending champion Bjoorn Borg, seeded no. 2, plays Antonio Zugarelli in the opening center court match of the contennial Wimbledon tennis championships Monday, but the status of Jimmy Conners' injured right thumb remained the chief pretournament topic of conversation.

Connors, the 1974 champion and no. 1 seed, prevailed on the referee for a 24-hour postponement of his first-round match against English lefthander Richard Lewis, now scheduled for Tuesday at the All England Lawn Tennis and Croquet Club.

Connors practiced at the Queen's Club there Saturday with an aluminum splint on his thumb. He injured the thumb last week by catching and jerking it in the throat of his steel racket as he reached for one of the backhands he thrashes two-fisted.

Connors, 24, is lefthanded, but the injury gives him pain on the backhand. He defaulted after his first-round victory in a Wimbledon tune-up tournament at Queen's Club last week.

At the time his injury was not, thought to be serious, but it has not healed. He had the thumb x-rayed on Saturday and was reportedly told he has a slight fracture.

Rumors circulated that there is a chance Connors might withdraw from Wimbledon, but he could not be reached at his London hotel today for comment.

Borg, 21, has been practicing in seclusion on grass courts for the past two weeks with his coach, Swedish Davis Cup captain Lenhart Bergelin, getting aclimatized to the fast turf on which he defeated Ilie Nastase in last year's men's singles final.

Nastase (seeded no. 6) plays Tom Gullikson, the lefthander of the two 25-year-old Gullikson twins from Onalaska, Wisc., and French Open champion Guillermo Vilas (No. 3) plays Jan Kodes, champ at Wimbledon in the boycott year of 1973, in Monday's other center court matches.

Except for Connors, no. 13 seed Phil Dent (recovering from the flu and also granted a postponment of his opener), and their opponents, Lewis and Jean Haillet, the entire men's field of 128 is scheduled to play first-round matches Monday.

Fourth-seeded Roscoe Tanner, the rocket-serving lefthander, is among the first players in action, opening on court. One against British Davis Cup player John Lloyd.

Tanner, who defeated Connors in the quarters-finals last year, has been in impjressive form this season, despite upset losses at Nottingham and Queens, and his boming service and improved strokes give him a good shot at the Wimbledon title.

Americans make up half the 16 men's seeds, with Brian Gottfried fifth seed, Vitas Gerulaitis eighth, Dick Stockton ninth and Stan Smith 11th, expected to figure prominently in the chase for the $25,500 first prize.

In first-round play, Gottfried faces Ramiro Benavides; Gerulaitis tackles Tom Gorman, Stockton meets Robin Drysdale and Smith, the 1972 champion, plays Dick Crealy.

Seventh-seeded Raul Ramirez, winner of the Queens Club title today, mets Peter Fleming in his first-round match.

Chris Evert, the No. 1 sed, and the other players in the women's singles draw of 96 who do not have byes are scheduled to begin Tuesday.