Chicago Cubs' second baseman Mark DeRosa was released from the hospital on Sunday night just a day after complaining of a rapid heartbeat, according to ESPN.com. DeRosa is expected to be examined by a cardiologist Monday and could return to the team by the end of the week, the team said. "He had an episode yesterday of an atrial dysrhythmia that he's had in the past that has lasted briefly," Cubs' doctor Stephen Adams told ESPN on Sunday. "This one had a bit of an extended period of time for which he contacted our head athletic trainer Mark O'Neal, who appropriately saw him and was with him."