Can a juror simply be replaced by an alternate?

Linsday Clancy's attorney Kevin Reddington today called for the removal of a juror after a note from other jurors claimed the person was not following instructions. The judge denied that request, but Reddington says an "inquiry" into the juror is set for tomorrow morning. So can a juror simply be replaced by an alternate? No, says Massachusetts criminal defence attorney Joe Serpa. "An inability to agree with the other jurors is not the same thing as an inability to serve," Se