Valdespin initially became angry, shouting across the clubhouse as he attempted to find out who had messed with his shirt. The sleeves of the shirt were shredded, according to Andy McCullough of the Star-Ledger. Furthermore, the front of the shirt said "NY <3 Valdy," while the back of the shirt said "El Hombre - 1."
In a blog post for the New York Times, Andrew Keh said that the prank had a dual purpose. While intended to be humorous, it was also meant to teach the rookie a lesson -- players are supposed to wear collared shirts to the ballpark.
The tension dissipated relatively quickly. Valdespin wound up wearing the shirt out of the clubhouse, laughing about it and posing for pictures.