JACKSON, MISS. -- Left-hander Pete Schourek, a 1987 graduate of Marshall High School in Falls Church, Va., began this season with shaky credentials.

He'd had two losing seasons and shoulder surgery had wiped out a third.

But, now, at 21, he could become the first minor-leaguer in 10 years to win 20 games. In 89 1/3 innings for the Jackson Mets of the Class AA Texas League, he has a 10-2 record with an earned run average of 3.12. He has struck out 70 and yielded 75 hits and 26 walks. He also threw two scoreless innings July 11 in the Texas League All-Star Game in Tulsa.

A 6-foot-5, 190-pounder, Schourek lost his first start of the season on April 10, when he was with the St. Lucie Mets of the Class A Florida State League. After he went 4-1 there he was promoted briefly to Tidewater of the Class AAA International League, where he won his only decision.

That gives him an overall record of 15-3. The last minor-leaguer to win 20 games in a season is Gene Nelson, now with the Oakland Athletics. He won 20 for Fort Lauderdale of the Florida State League in 1980.

"Winning 20 would be awesome," Schourek said. "I'm not sure how many starts I have left, but it's definitely in the realm. I'm maybe lucky, not unbeatable." Certainly not unbeatable, but he's had only one bad outing, giving up eight earned runs in 2 2/3 innings July 16 against the Diablos in El Paso.

"Pete has a major league fastball and curveball, but not consistently," said Bob Apodaca, Jackson's pitching coach and a former New York Mets pitcher. "That's what the minor leagues are all about. What sets him apart besides his stuff is his composure and his willingness to learn. He's the type of individual who can listen to something one second and do it the next."

Schourek signed a letter-of-intent with Auburn after graduating from Marshall three years ago. Then he was drafted in the third round and chose professional baseball instead. That first summer he was 4-5 with Little Falls (N.Y.) of the New York-Penn League. He missed the entire 1988 season because of shoulder surgery and had his problems at Columbia last season.

He pitched 140 innings and was 5-9 for the Mets of the Class A South Atlantic League. So far this season he has totaled 140 1/3 innings, and he may be tiring.

"Sometimes it's hard to raise my arm the day after a start," he said. ". . . I just plan on getting my rest and keeping up with my arm exercises."

"We're going to monitor him," said Jackson Manager Clint Hurdle. "We could stretch him between starts or get him out of there sooner. But this is his time. . . . We're not going to stop him. This is a tough grind."

The Mets listed Schourek as one of the 40 players on their major league roster last winter, so he was affected by the lockout and that might have contributed to his first-game loss, although the score was only 2-0.

"I had thrown about eight or nine game innings, one in the big league camp, prior to that," he said. "I wasn't as sharp as I could have been."

Gerry Hunsicker, the Mets' director of minor league operations, explained why Schourek was protected: "We knew what we had and we didn't want to take a chance on losing him. Left-handers are few and far between in our organization."

Tommy Thompson, manager of the Tulsa Drillers, thinks Schourek is the best left-hander in the Texas League. Advised of Thompson's comment, Schourek said: "I'm flattered, of course. It makes me want to work harder and show that it's not a mistake."