Don Mattingly, in the midst of his hottest hitting streak of the season, is likely to be sidelined for two weeks. Mattingly suffered a strained muscle below his right rib cage Friday night while taking extra batting practice before the Yankees' game against the Mariners.

Yankee Manager Billy Martin said the club would decide Saturday whether to put Mattingly on the 15-day disabled list. He gave every indication that the Yankees would make that move."This is quite a setback, quite a set- back," said Martin, who appeared stunned by the development.

Mattingly said Mariners physician Mitch Storey told him he should be 100 percent in 7 to 10 days. But Martin said, "It could take 10 to 12 days, maybe two weeks. If we do it, we'll put him on the DL for 15 days and backdate it to (Friday)."

In that case, Mattingly would miss 12 games: the remaining nine games on this trip - three each in Seattle, Oakland and Baltimore - and three games at home against Boston. He would be eligible to play again June 10.

Mattingly noticed that the timing of the injury was dreadful. He had hit .421 (24-for-57) in his past 14 games, with 7 doubles, 4 homers and 13 runs batted in. He was on a seven-game hitting streak that raised his average to a season- high .320. And Mattingly is a career .411 hitter in the Kingdome.

"This is not a good time and this is not a good city to be missing games," he said. "I felt like I was getting to be where I wanted to be as far as consistency and driving the ball. But I have no fears. I know my stroke will be there when I get back. Once you find it, you know you have it.

"This won't hurt us at all. Well, it may hurt us a little. But I don't think it will keep us from winning any games."