The source of the explosion? Corey Hart's knee:

First baseman Corey Hart will miss the next three to four months with an injured right knee that requires surgery, the team announced on Friday. Hart's knee started to swell up during offseason workouts, and an MRI revealed a torn meniscus and other damage to the joint that will be surgically repaired by Dr. William Raasch on Tuesday.

Mat Gamel will likely replace Hart at firstbase -- a certain downgrade from Hart's normal output.

What does this mean for the Pirates and their fans? Fewer blowouts, I hope.