O's game blog: A matchup of division leaders as the second half begins

The Oakland A's have had a terrific first half. If their 59-36 record didn't tell you that, maybe their run differential will. Not only is Oakland's plus-145 run differential the best in the majors, the 2014 A's are one of five American League teams to have a run differential of plus-139 or better at the All-Star break since 1940. The Orioles are on this list twice. Plus-168: The 1969 Orioles Plus-157: The 1998 Yankees Plus-149: The 2001 Mariners Plus-145: The 2014 A's Plus-143: The 1966 Orioles The A's have had the best record in MLB since June 18. The next closest team in the AL in run differential is the Angels at plus-89. Oakland has won eight of 11 and 17 of its last 25. The A's are 30-15 at home and have won six in a row and 11 of 12 there. Over their last 11 games, Oakland pitchers have allowed one run or less and have an ERA of 1.73. This is quite a challenge for the O's as the second half begins. Meanwhile the Orioles offense ended the first half producing seven hits or fewer for the last five games, with 28 hits total. Over those five games, the Orioles batted just .199 with three homers and 12 runs. Chris Tillman (7-5, 4.11 ERA) takes the mound tonight against Oakland's Jeff Samardzija (1-1, 2.40 ERA) who will be making his third Oakland start after going 2-7 with a 2.83 ERA for the Chicago Cubs. Tillman ended the first half going 2-3 with an ERA of 2.47 in his last seven starts. In that stretch, he went seven innings or more four times with six quality starts. While Samardzija has never faced the Orioles, Tillman is 1-0 with an ERA of 1.96 in three career starts against the A's.