By Gary Brooks
SportsLine Baseball Editor

Division-leader matchups highlighted by Martinez vs. Cone

Thanks to the turbulent bullpens of the Arizona Diamondbacks and Boston Red Sox, we've got a couple of first-place showdowns to watch this week.

The D-Backs are in San Francisco to take on the Giants and the Red Sox are at home facing the hated Yankees, with the top spots at stake in the National League West and American League East. It's hard to say that games played in May will have a decisive outcome in the 162-game run, but both offer early indications where strengths in divisions lie.

Pedro Martinez matches up with AL ERA leader Dave Cone Tuesday. (AP)

Arizona, which resided atop the NL West standings for the first time ever Sunday morning, fell a game behind the Giants by losing to the Rockies. But Monday through Wednesday, they get a personal say in whether they are better than San Francisco.

If the Diamondbacks hadn't lost five of their first six games, blowing four saves, it would be the Giants chasing them.

IT'S THE SAME STORY in Boston, where the Red Sox blew six of 10 save chances while reliable closer Tom Gordon was on the disabled list. Gordon is back and Boston started this week having won eight of its past 10.

Tuesday through Thursday, the Sox face off with the Yankees, whose recent slump (N.Y. has lost five of six) has enabled Boston to pull within a game in the AL East. Boston's 20-16 play isn't as surprising as the Yankees' 21-15 record. New York has not hit the ball well recently and scored just two runs while ending their five-game losing streak Sunday.

"We know we're not the team that we were last year,'' Yankees center fielder Bernie Williams said after Saturday's loss to the White Sox at Yankee Stadium. ``We have the talent but things that happened last year are not happening this year. This year is a new challenge.''

That challenge reaches its toughest test Tuesday when Red Sox right-hander Pedro Martinez takes the mound at Fenway Park. Martinez has been phenomenal: 7-1 with a 1.81 earned-run average and 91 strikeouts and just 11 walks.

The Yankees can be confident with Dave Cone -- 4-1 with an AL-best 1.33 ERA -- taking the mound.

It looks like the best pitching duel of the season so far. It can't get any better than Cone's last outing, a 1-0 loss to the Angels in a superb matchup with Chuck Finley at Yankee Stadium.

Aside from the matchup of Cy Young Award winners, there are other points of interest in the series.

New York shortstop Derek Jeter has reached base in all 36 games this season. Wednesday, another quality pitching matchup could develop. Hideki Irabu, who has come around since altering his pitching motion to get up on his toes before he delivers the pitch, faces Red Sox rookie Juan Pena, who has won both of his first two major-league appearances and brings in a 0.69 ERA.

What else to watch

• Arizona's Luis Gonzalez takes a 28-game hitting streak into the big series against the Giants. Colorado's Larry Walker, the NL batting average leader, takes a 17-game streak home to Coors Field where the Rockies face the Cincinnati Reds. Raul Mondesi and Cliff Floyd each carry nine-game streaks into Monday.
• While the Giants and Diamondbacks face each other, it's possible the Dodgers could leap past both of them and into first place in the NL West. Los Angeles started the week a game and a half behind the Giants, and host Houston and St. Louis this week.
• Philadelphia Phillies ace Curt Schilling will try to become the first seven-game winner in the NL Monday at Montreal.
• The New York Mets return home to face the Milwaukee Brewers while trying to catch the slumping Atlanta Braves whose lead in the NL East is just 1½ games.
• Braves right-hander John Smoltz needs six strikeouts for 2,000 in his career. He'd be the 51st to reach the mark and should do it Friday against the Chicago Cubs at Turner Field.
• The Oakland A's have hung right behind Texas in the American League West and a large part of the reason is Mark McGwire. Well, at least, indirectly. T.J. Mathews, who was acquired along with Blake Stein and Eric Ludwick, in the trade with the St. Louis Cardinals for McGwire, is 5-0 with a 1.13 earned-run average in relief. Oakland travels to Kansas City and Minnesota this week, while the Rangers host Tampa Bay and travel to Baltimore.
• Mo Vaughn has been on an overwhelming hot streak since his poor series last week in his return to Boston. Entering the week, Vaughn had 10 hits in his last 22 at-bats with 14 RBI in six games. He and the Angels spend the week on the road at Baltimore and Tampa Bay.
• Greg Maddux faces the Cubs again Thursday. Having lost three straight, Maddux has given up 10 or more hits in his past five outings. In 50 1/3 innings he's allowed 79 hits, the most in the NL.
• Through the weekend there had been 35 grand slams hit. The season record is 141. At the current rate there would be 156 this season.