As the second half of the NBA season began with the Boston Celtics mired in an apparently hopeless NBA-worst 13-38 season, All-Star guard Paul Pierce announced Wednesday that he would miss the rest of the season with a rather unusual cough. 'I, uh, cough cough, must have come down with a little something while I was in Vegas, cough, cough,' said Pierce, who held his hand in front of his mouth while seeming to repeatedly pronounce the word 'cough' instead of actually coughing. 'I don't, cough, sniffle, know if I can put in that many minutes in my weakened condition.' Celtics coach Doc Rivers said the team was devastated by the report of the injury, especially as it came so soon after news of the mysterious limp that afflicts forward Wally Szczerbiak whenever Celtics games are not broadcast on national television. 