From the blog of Ken Gurnick:
Dodgers left-hander Clayton Kershaw will miss his scheduled start Friday night in San Francisco after bruising his right shoulder running into the fence at Dodger Stadium Sunday shagging fly balls during batting practice, according to manager Joe Torre.
That's his non-throwing shoulder, so no hopefully no big worries there. The move has the benefit of resting Kershaw during a season where he has already increased his workload by more than 50
pitches innings over last year (the "Verducci Effect" warns against increases of more than 30 innings per season for pitchers under 25).
UPDATE: Thanks to Tripon for the lowdown:
Kershaw's pitched 169 innings combined last year in the majors and minors.
He's at 159 innings this year. He can probably pitch 190 innings this year.