Sentence:  A terrible fielding error from Tony Graffanino proved costly. [...] Aaron Rowand collected an RBI double to get them off the mark before Graffanino's <WSD>brainstorm</WSD>. Juan Uribe hit a roller to the second baseman, who let the potential inning-ending double-play ball roll under his glove, leaving runners at first and third bases. 
Meaning of the word marked with <WSD> tags:  An unexpected mental error.