Around the diamond

One of the year's biggest surprises has been Toronto outfielder Barry Bonnell , a lifetime .261 hitter who batted .220 in 1981 but has been hitting in the . 350s this season.

''Mechanically, I haven't changed a thing,'' says Bonnell, who currently stands second in the American League batting race. ''What I've done is flip-flopped my priorities as a hitter. Other years with me it's always been pitch selectivity first, then aggressiveness. But this year I decided to go out and challenge the pitchers by swinging at anything I thought I could hit, even if it was a trifle outside the strike zone.''

Pittsburgh reportedly had a flood of offers for catcher Tony Pena just prior to the June 15 trading deadline, the most consistent calls coming from the Los Angeles Dodgers. Pena, a Pirate untouchable, can also play the outfield or third base. . . Reportedly the Atlanta Braves were close to a deal with the New York Yankees for pitcher Rudy May until Doyle Alexander was injured punching out a concrete wall and had to go on the disabled list.

There's a lot of smoke, and maybe some fire, in rumors that Yankee owner George Steinbrenner will ask the Cincinnati Reds for permission to talk with manager John McNamara at the end of the season. So far Steinbrenner has not gotten what he wanted from current manager Gene Michael, which was more wins on the road. McNamara, who faces a long rebuilding period in Cincinnati, is expected to jump at the chance to work for the Yankees.

At the rate he's going, Oakland outfielder Ricky Henderson will break Lou Brock's single-season stolen base record of 118. In fact, Henderson has confided to friends that he hopes to make it 160. Another speedster worth watching is rookie outfielder Alan Wiggins of San Diego, who had 44 steals in his first 48 attempts this season.

Third baseman Tim Wallach of the Montreal Expos set a rare standard for No. 7 hitters in May when he batted .367 and drove in 23 runs. All this from a player who used to be considered a bad-ball hitter.

The Los Angeles Dodgers, who have been looking for a dependable fifth starter all season, may be only a few weeks away from bringing up 19-year-old left-hander Sid Fernandez from the minors. Fernandez, recently promoted from the Class A Vero Beach (Fla.) Dodgers to the Triple-A Albuquerque Dukes, has already pitched two no-hitters this season. Sid's out-pitch is a fastball that appears to rise against the hitter like the wind. Said Albuquerque manager Del Crandall: ''Fernandez releases the ball from such a low angle that he actually looks as though he's throwing up at the hitters. His deceptive motion is the closest to Tom Seaver's that I've ever seen.''