CHICAGO (AP) Cubs left-hander Jon Lester has not allowed a hit through six innings against the Pittsburgh Pirates.
There is no score on Sunday.
Lester walked David Freese in the first inning and Francisco Cervelli to lead off the second. Since then, he has retired 15 straight batters.
The 32-year-old lefty, who has thrown 91 pitches, is seeking his second career no-hitter and the second for the Cubs this season.
Lester, then with Boston, threw a no-hitter on May 19, 2008, in a 7-0 win over Kansas City in what his first complete game.
Cubs ace Jake Arrieta no-hit the Cincinnati Reds on April 21 in a 16-0 victory.