CHICAGO — Matt Dominguez’s expression hardly changed as Brandon Barnes teasingly sang “Happy Birthday” to him while Dominguez gave an interview Wednesday afternoon. “Spalding,” as Dominguez is nicknamed because of a fuzzy mop of hair reminiscent of a tennis ball, refused to give his pal any satisfaction. Dominguez, who also goes by the unflattering “Sloth” because of his sleepy eyes and aforementioned fuzzy hair, doesn’t let opponents or teammates elicit a reaction out of him. Whether celebrating his 24th birthday like he did Wednesday or after a disappointing night at the ballpark, the Astros third baseman rarely changes his mien. He’s steady, never getting too excited or too dejected. Unless [...]