It takes all kinds, and for Exhibits A and B, we give you Chris Knapp and Dave Parker.

Halfway to becoming a 20-game winner, Knapp quits baseball midway through the American League season.

Ten days after complicated surgery to rearrange his shattered face, Parker puts on a hockey goalie's mask (then yanks it off and slugs a key triple) and goes back to work terrorizing National League pitchers.

Two guys who have been openly unhappy with their contracts, two totally different stories.

Knapp was 12-7 for the White Sox as a rookie, 10-6 in his half-season for the Angels - all he has to do is keep it up to arrive in the big money League. And at 24 he chucks it because he wants his $40,000 salary for 1978 upped, right now, to $70,000.

Well, it's not only the money now, it's the principle, says Knapp, insisting his departure is permanent: "I decided to step out while I'm still young enough to start over (in another career). I just didn't like the way I was being treated . . . the atmosphere . . . the way professional sports is going . . ."

So Knapp, who never did sign a California contract after demanding $100,000 in the spring, and wife and daughter head home for Sarasota, Fla.

Parker, meanwhile, wants his estimated $200,000 salary upped to around $500,000 come offseason or he plays out his Pittsburgh option next year. But, until then, he declares, "I apply myself the same as I would if I was making $5 million. It's a pride thing . . . I'm just a hard-nosed, aggressive player."

Parker wasn't supposed to take batting practice last week but went to a public park and sharpened up on the pitching machines - a few days after "they cut from the inside, pushed out my cheek, put a lot of packing in there, drilled two holes on each side of my eye pulled the cheek up with some wire, and evidently did a very good job."

Sunday, he came off the disabled list and batted against San Diego with a mask he painted in Pirate gold and black. After a walk, ground out and fly out, he discarded it and hit his triple.

When he reached third, he donned a special batting helmet with two ear flaps, a chin strap and a football face guard. "No pain at all," he said . . .

From the defaced face to the defaced baseball case, NL President Chub Feeney has let Dodger pitcher Don Sutton (who threatened to sue) off without suspension. Feeney only warned him he's asking for bigger trouble if he again is caught using scuffed balls as the umpires who ejected him Friday against St. Louis alleged . . . And one more with second thoughts on baseball: shortstop Pat Rockett, demoted by Atlanta to Richmond after hitting .141 through June. "I'm in good shape, I'm only 23, I've thought maybe I'll go to Texas and play football," cogitates Rockett, a star wide receive in high school . . .

The NCAA reduced the number of football scholarships a school may carry at one time, from 120 four years ago to 95 now, then enacted a codicil this year under which red-shirted players are counted against the limit. A lot of athletes are caught in the squeeze. Case in point, Kentucky: Coach Fran Curci says as many as 13 of his players may lose their grants. Curci, correcting a published report that his No. 2 quarterback Bill Tolston was among those being cut off, said the cuts at UK were necessary because "we've done a good job of keeping our players. The NCAA rule figures there is going to be more attrition that we've had. We're opposed to cutting any athletes and we'd like to find a better solution . . ."

Michel Pollentier, the Belgian bicycling ace kicked out of the Tour de France for allegedly cheating the drug testers when he was leading the big race, said yesterday, 'Fifty percent of the competitors here are using stimulants of one kind or another." He and his countrymen and the Union of Cyclists failed to persuade the International Jury of Cycling, meeting at I'Alpe d'Huez, France, though, to reduce his sentence of a two-month ban, 5,000 Swiss-franc' fine and an as signed overall race time matching the last-placer's. Pollentier's fellow Belgian cyclists threatened Sunday to quit the Tour, crying he had been disqualified because he was Belgian, not French. But - the jury belatedly announced yesterday that a French contestant, Antoine Guiteierrez, also had been disqualified, and for the same irregularity: trying to trick the urine test for doping by concealing a rubber tube of old, unadulterated urine under his armpit . . .

Another jockey tragedy: George Gomez, an apprentice who suffered multiple injuries in a spill at Miami's Calder Race Course May 19, developed complications and died Sunday. Calder's leading rider in 1977, winning 80 times in the fall meeting, Gomez, 28, had been back on the track only a week after being out nearly three with a back injured suffered at Hialeah. He leaves a wife, a 4-year-old daughter and a 7-month-old son . . .

A free tennis clinic at 16th and Kennedy precedes today's action in the Washington Star International: Arthur Ashe and teaching pros to show an expected 1,500 youngsters techniques and basics 10 a.m. to noon; first 1,000 receive a free tennis hat . . . Would-be baseball pros, the Los Angeles Dodgers will conduct a tryout camp at George Mason U. in Fairfax, 9:30 a.m. Thursday. Jim Garland, Dodger area scouting supervisor, and Jim Brokke (241-5027), will run the proceedings, all the way down to a radar gun to clock pitching velocity . . . Not only have the Washington Metros of the Eastern Basketball Association become the Baltimore Metros, but they've named Larry Cannon coach and general manager. Cannon, 31, is the former La Salle star who scored 17.9 points a game in four ABA years, only to find his playing career curtailed by a tendency to blood clotting . . .