OAKLAND, Calif. -- The last time Adam Rosales hit a homer, it wound up not counting after a replay flap at Cleveland on May 8.
On Friday night at the Coliseum, Rosales knocked a clear homer over the wall in left field in the eighth inning off James Shields to give Oakland a 2-1 victory over the Royals.
The day after Rosales' drive in Cleveland, Major League Baseball acknowledged an error had been made and that the initial call should have been reversed. A reversal would have given Rosales a game-tying homer with two outs in the ninth.
Josh Donaldson had ended Shields' streak of scoreless innings at the Coliseum at 15 in a row by cracking a homer to left on a 3-1 pitch in the seventh inning, tying the score.
Donaldson, emerging as a potential All-Star selection for the A's, has a six-game hitting streak during which he is batting .550
After Donaldson's homer, which led off the inning, Shields struck out the side. He finished with nine strikeouts in all, tying his season high.
A's starter Jarrod Parker, struggling to regain his peak 2012 form, put together his best start so far in 2013, going a season-high seven innings and allowing one run, matching his season low. He struck out five and walked two.
Shields has allowed more than three runs in just one of his nine starts this season; in his past four outings, he has given up six earned runs in 31 innings.
Oakland is last in the league in batting in May, entering the game with a .217 (101 for 465) average with 41 runs in 14 games.
Grant Balfour picked up the save for Oakland, his 25th in a row. His last blown save came more than a year ago, on April 29, 2012. The Royals did not get a runner past first base after the fourth inning.
A's right-hander Jarrod Parker, coming off a decent start at Seattle last week, gave up a one-out double to Kansas City catcher Salvador Perez in the third inning, then a two-out bloop double over shortstop to leadoff hitter David Lough that sent in Perez.
It was the first major-league RBI for Lough, called up earlier in the day; Lough also spent 20 days with the Royals last season.
Kansas City had to place outfielder Jarrod Dyson on the disabled list with a high right ankle sprain earlier in the day -- the first time that the Royals have used the DL since the start of the season.
Lough also threw out Brandon Moss trying to stretch a single into a double on a liner into the gap in right in the fourth.
Shields allowed four singles and a walk in the first five innings, stretching his string of scoreless innings at the Coliseum to 14. His previous appearance at Oakland, Shields threw a complete-game shutout.
Perez extended his hitting streak to eight games. He entered the game batting .380 (19 for 50) since April 30.
NOTES: The A's announced before the game that left-hander Brett Anderson, the team's No. 1 starter, has a stress fracture in his right foot, which will be immobilized for the next four weeks. Anderson said the injury was separate from the right ankle sprain that put him on the DL on April 30; he felt it while running in the outfield on Monday afternoon. ... Dyson injured his ankle while trying to make a catch on a home run by the Angels' Mike Trout on Wednesday. ... Oakland selected left-handed reliever Hideki Okajima from Triple-A Sacramento on Friday afternoon and designated right-handed reliever Chris Resop for assignment. Resop had allowed 12 runs in his past 11 appearances. ... A's catcher John Jaso was not available for anything other than possible pinch-hitting duties because his right shin remained stiff and sore after being hit by a pitch from Texas' Alexi Ogando on Wednesday. ... A's manager Bob Melvin said outfielder Chris Young (left quad) is expected to come off the DL on Saturday.