Athletics right-hander Ben Sheets could miss the remainder of the season after he was placed on the disabled list Saturday. Sheets said his elbow has swelled far more than usual his past few starts. "It's possible," he said of missing the rest of the season. "I don't know. I don't like the fact it's so swollen. It's been so up and down the last two weeks, so up and down all year." Sheets will visit his own orthopedist in Dallas on Tuesday. He already has been checked by Oakland's doctors, and general manager Billy Beane said the team will wait to disclose a diagnosis until Sheets gets a second opinion. "We wouldn't want to speculate," Beane said. "We'll have a more definitive diagnosis after that."