Dana White won't like the sound of this. According to a Tatame report, UFC middleweight champion Anderson Silva suffered a knee injury in training. He will be assessed later today, but it's very possible that it could impact his July 7th bout with Chael Sonnen at UFC 148:

UFC middleweight champion, Anderson Silva was honored by Brazilian Taekwondo Confederation this Monday, but the day wasn't all about good news. The fighter revealed to the press that he got his knee injured on a training session, and that he's getting tested today to see how serious it is. Despite that, the champion was not limping during the ceremony, and seemed optimistic about the recovery.

The headline of the Tatame piece states that Anderson says the bout is still on, but that is not stated explicitly in the article itself. We will just have to wait and see what the deal is. If he is indeed too injured to take part in the Sonnen bout on July 7th, that would obviously be a devastating blow to the card.

Update - Anderson tweeted a picture of himself training a few minutes ago and basically said that he's okay. Here's the translation by BE member mollcutpurse:

Folks, my knee’s doing very well, thanks! Relax, July 7th I’ll be doing my job. Oss.

SBN coverage of UFC 148: Silva vs. Sonnen II