Rapid Reaction: Orioles 4, Red Sox 3

BALTIMORE -- It's official: The Red Sox will have much to do with deciding the winner of the American League East.

Their 4-3 loss to the Orioles on Saturday night left Baltimore tied with the New York Yankees for the division lead. The Sox have four games left: one against the Orioles on Sunday, three against the Yankees in the Bronx over the following three days while the Orioles will be in St. Petersburg for three games against the Tampa Bay Rays, who are still clinging to faint hopes of sneaking in as a wild card.

The Sox will be sending right-hander Zach Stewart, who was lit up for nine runs in three innings against the Angels in his only other start for the Sox this season, against the Orioles on Sunday. They have their two best pitchers going Monday and Tuesday against the Yankees: Clay Buchholz and Jon Lester, in that order.

Imagine: The AL pennant could be decided Wednesday in what is likely to be the last start of Daisuke Matsuzaka's Red Sox career.

Sox rookie left-hander Felix Doubront pitched very well Saturday, striking out 10 and walking just one in seven innings. But he gave up a two-run home run to Chris Davis in the fourth, Davis' 30th of the season, and a solo home run to Orioles teenager Manny Machado that broke a 3-all tie in the seventh.

The Sox have now lost 89 games, assuring them of their worst record since 1992, when they went 73-89. They must win out to avoid matching or exceeding the 72-90 record of the 1966 Sox, the worst record for a Boston team in 46 years.

The Orioles, meanwhile, added to their extraordinary record in one-run games. They are now 28-9 in one-run games, 72-0 in games in which they lead after seven innings.