Roberts returns to Orioles' lineup

Second baseman Brian Roberts is back in the lineup after missing last night's game in Kansas City following a root canal. Vladimir Guerrero will sit for the first time. Brian Roberts 2B Nick Markakis RF Derrek Lee 1B Luke Scott DH Adam Jones CF Matt Wieters C Felix Pie LF Mark Reynolds 3B Robert Andino SS Jake Arrieta RHP Here's the Royals' lineup: Aviles 2B Cabrera CF Gordon LF Butler DH Francoeur RF Betemit 3B Ka'aihue 1B Treanor C Escobar SS Davies RHP Arrieta is 3-0 with a 2.12 ERA in three starts this year against the American League Central. He beat Chicago on April 29, Minnesota on April 19 and Detroit on April 4. Arrieta is 4-2 with a 4.75 ERA in eight career starts against Central opponents. The only team he hasn't beaten is Kansas City. The Orioles have scored 36 runs in Arrieta's six starts, including 24 while he was in the game. In the 16 combined games started by Chris Tillman, Jeremy Guthrie and Brad Bergesen, the Orioles have scored 56 runs, and just 22 while those three pitchers were in the game. Scott is batting .344 (11-for-32) with a double, four homers, nine RBIs and six runs scored in his last eight games since April 24. He's homered in four of his last six games. Down on the farm, LJ Hoes collected five hits today and Miguel Abreu launched Single-A Frederick's first grand slam in a regular-season game since April 25, 2010, as the Keys defeated Winston-Salem, 9-3, at Harry Grove Stadium. Hoes is the first Frederick player to record five hits since Bobby Stevens on May 10, 2009. Hoes also had an RBI and two runs scored. Bobby Bundy (3-2) won his third consecutive decision, striking out eight in 5 2/3 innings. Unfortunately, center fielder Trent Mummey was injured in the top of the second inning. According to the Keys' game summary, Mummey raced back on a ball in the left-center field alley and dived to his right. As he descended, he flied head-first into the outfield wall and laid on the warning track for some time. An ambulance took Mummey to Frederick Memorial Hospital, and initial reports showed that he was alert and had feeling in all of his extremities. The injury occurred on a two-RBI triple from Winston-Salem catcher Luis Sierra. The Sun's Jeff Zrebiec tweeted that shortstop J.J. Hardy will begin his injury rehab assignment Friday at Triple-A Norfolk.