Apr 12, 2010 6:39 AM EST

Red Sox outfielder Jacoby Ellsbury bruised his ribs in a collision with third baseman Adrian Beltre on Sunday.

Boston was two outs away from beating Kansas City when Mitch Maier sliced a fly ball down the left-field line.

Ellsbury, who was playing straightaway, got a good jump and sprinted toward the line. Beltre, believing Ellsbury was shaded more toward center, put his head down and ran back.

The outfielder only had eyes for the ball as he went into a slide and lifted his glove in anticipation of a catch. Beltre, shocked when he realized too late that Ellsbury was in his path, drove his right knee into Ellsbury's ribs as he tumbled over the outfielder, the ball hitting his glove and falling free.

Ellsbury screamed, then clutched the left side of his chest as manager Terry Francona and trainer Mike Reinold made their way from the dugout.

"He was in a lot of pain when we got there," Francona said, "and he was still in a lot of pain when I came back in here."

X-rays on his ribs were negative.

"It's sore, but I'll be fine," Ellsbury said. "He kneed me in my ribs so that was the thing I was worried about, a broken rib or something like that. I'm sure there's going to be quite a bit of swelling because it's a little tough to breathe, but I think I'll be fine."

Via ESPN