Just a week into the season and the Rangers have issues with the top two spots in their starting rotation. LHP Matt Harrison has not been on the field the last two days while receiving treatment for soreness in his lower back, which bothered him during his poor outing on Saturday. Rangers officials said Harrison is still scheduled to pitch on Thursday at Seattle, but he has done no throwing since Saturday and his scheduled bullpen day would be Tuesday. In addition, RHP Yu Darvish came out of Sunday’s game with torn, irritated skin on his right ring finger. Manager Ron Washington said Darvish is expected to make his start, as scheduled, on Friday at Seattle. “I don’t think it was as bad as it was during his first start,” Washington said. “This won’t be a long-lasting thing. He’ll get rid of it and somewhere in the schedule there will be time to give him a little extra rest.” Harrison’s issue could be more troublesome. If his back does not respond to treatment, the Rangers may have to consider a pitching move for Thursday. That could mean asking RHP Derek Lowe or LHP Michael Kirkman to fill in. Kirkman was up and warming in the eighth inning Sunday, but sat down and yielded to RHP Joe Nathan for the ninth, even though it was not a save situation.