OAKLAND, Calif. — Justin Grimm is learning first-hand what Frank Sinatra was singing about long ago.Grimm was voted as the American Leagues top rookie last month after taking over in the Texas Rangers rotation for Matt Harrison, but the results have been lacking this month.As the Chairman of the Board once crooned, riding high in April, shot down in May.Thats life, and thats Grimm. And with two rotation candidates on the comeback trail, he cant keep getting beat if he wants to get back on top in June.Grimm lost his third straight start Monday night, allowing five runs in five innings, and A.J. Griffin allowed only one run in seven innings as the Oakland As snapped the Rangers four-game winning streak with a 5-1 victory.April was a lot more fun, especially between starts, Grimm said. Its a lot more fun when things are going good for you. But youve got to find ways to stay mentally strong. Its a big difference. Oakland has beaten the Rangers five straight times at O.com Coliseum dating to last year, a stretch that includes a second-ending three game sweep that allowed the As to pass the Rangers for the American League West title.The As scored twice Monday with two outs in the second, an inning kept alive by a two-out walk to the .234-hitting Derek Norris in the No. 8 spot in the lineup, and Grimm elevated fastballs to Yoenis Cespedes and Brandon Moss that resulted in back-to-back homers with one out in the third.They did their job, Grimm said. I left a couple pitches over the plate when they were supposed to be inside. That cant happen.The walk to Norris, on four pitches, wasnt as costly in Grimms mind as the mistakes he made to Cespedes and Moss. Grimm (2-3) was also lamenting that he made too good of a pitch in the second to Daric Barton, whose broken-bat grounder to Adrian Beltre was hit a tad too slow for the inning-ending double play.Norris followed, pushing Barton to second, and No. 9 hitter Eric Sogard and leadoff man John Jaso followed with singles for a 2-1 lead.Griffin took over from there. He had allowed a two-out solo homer to Mitch Moreland in the second, but scattered four more singles. Four times the Rangers started the inning with a hit, only to have that runner wiped immediately wiped out.The Rangers also werent particularly pleased with plate umpire Lance Barksdale, who called out five Rangers on strikes.Thats the way it is, said shortstop Elvis Andrus, who was caught looking in the first and the sixth. Were never going to see the ball as a strike. Were always going to talk about it.The key for Griffin, said manager Ron Washington, was his breaking ball. The right-hander was able to change speeds with it and throw it for a strike. That pitch and a good fastball kept the Rangers off-balance.After Moreland got him, we just couldnt do anything with him, Washington said.Grimm, meanwhile, has allowed five runs in consecutive starts and hasnt won since April 26. The Rangers know that right-hander Colby Lewis and left-hander Martin Perez could be options by the end of the month or in early June if Grimm cant shake out of his May funk.Im not concerned about him, Washington said. Each game that he pitched and he lost, he kept us in the ballgame. Tonight we only scored one run. Hes out there battling and hes out there fighting.Said Grimm: Im going to keep my head high, show up tomorrow and get my work in, and look to turn the corner.