The Oakland Athletics placed right-hander Paul Blackburn on the 10-day disabled list Friday with a right hand contusion.Blackburn, 23, left Tuesday night's start in the fifth inning against the Baltimore Orioles after a liner struck him on the right wrist. The move is retroactive to Aug. 23.Blackburn, who was recalled from Triple-A Nashville on July 1, is 3-1 with 3.22 ERA in 10 starts with Oakland in his debut season. He started on Tuesday at Baltimore and tossed four scoreless innings before he was hit on the hand by Trey Mancini's comebacker to lead off the fifth inning.Blackburn is 2-0 with a 4.38 ERA and .315 opponents batting average over his last five starts with the A's after going 1-1 with a 2.25 ERA and .212 opponents average over his first five starts.The Athletics also recalled right-hander Michael Brady and outfielder Mark Canha from Nashville.Brady, 30, joins the A's for the fourth time this season and is 0-0 with a 4.56 ERA and .270 opponents batting average in 10 relief appearances over his first three stints. He is 3-1 with a 3.21 ERA in 17 games, including eight starts, at Triple-A.Canha, 28, returns to Oakland for his fourth stint and is batting .210 with four home runs and 10 RBIs in 34 games. He went 5-for-16 (.313) with a home run and three RBIs in five games during his most recent stay Aug. 2-10. He went 12-for-32 (.375) with six walks and four RBIs in nine games with Nashville following his Aug. 11 option. Canha is batting .283 with 12 homers and 50 RBIs in 75 games overall at Triple-A.Canha, who has appeared in 15 games in right field, 12 in left field, seven in center field and two at first base with Oakland, takes the roster spot of Rajai Davis, who was traded to the Boston Red Sox on Wednesday for minor league outfielder Rafael Rincones.