Fantasy proved painful for Jennifer Steinbrenner Swindal, daughter of legendary Yankees owner George Steinbrenner, when she injured herself while playing at the team’s Women’s MiniFantasy Camp yesterday. During the Yankee vice chair’s first at-bat in a game at the Bombers’ Steinbrenner Field spring training complex in Tampa, Fla., she injured her leg while running out a grounder, according to reports. But after being treated, she returned to the dugout to watch the final inning. The camp runs through tomorrow. Pros who’ve attended in the past include Tino Martinez, Mickey Rivers and Darryl Strawberry.