Quarterback Jay Jeffrey, reinserted late in the game, drove Baylor 72 yards to a field goal with 22 seconds left that defeated Texas A&M, 19-17, yesterday in a Southwest Conference game in Waco.

Freshman Marty Jimmerson's 21-yard field goal was his fourth of the game.

A&M (4-2, 3-1) got its first SWC loss after freshman linebacker Kevin Hancock had recovered Thomas Sanders' fumble at the Baylor 28. Baylor (4-3, 2-2) is the defending SWC champion.

Jeffrey was ineffective on his first series after replacing Mike Brannan, who was making his first start since the 1979 Peach Bowl. And Baylor's victory overshadowed the performance of A&M wide receiver Mike Whitwell, a 171-pound senior who made a fingertip catch on a 41-yard scoring pass and set up both of A&M's other scores with catches.

He grabbed a 50-yard pass from Gary Kubiak to set up David Hardy's 19-yard field goal with 10 seconds left in the first half, and leaped high for a 39-yard completion at the Baylor 11 to set up A&M's final score, a five-yard run by Johnny Hector.

Jimmerson also kicked field goals of 50 yards, a personal high, 20 and 38. He was wide with his first field goal attempt, from 30 yardS.

That miss wasted a Baylor recovery of a Sanders fumble at the opening kickoff at the A&M 17, but Baylor turned a fumble by Hector at the A&M 39 into Jimmerson's first field goal.

The Bears took a 10-0 lead on a 75-yard drive as Alfred Anderson pulled away from A&M linelacker Mike Little at the eight and fell into the end zone.

A&M came back on the 41-yard pass to Whitwell, who pulled the ball in with his fingertips going full-speed at the two. It was the longest scoring play the Baylor defense has given up this year.

Baylor padded its lead as Jimmerson kicked his 20-yarder after a 78-yard drive had stalled at the A&M two.

Although A&M ranked 11th nationally in rushing defense, Baylor runners totaled 253 yards on the ground. Walter Abercrombie ran 28 times for 122 yards, just eight yards short of what the entire A&M backfield got rushing.