MURFREESBORO, Tenn. — Dr. Sidney A. McPhee, president of Middle Tennessee State University for more than a quarter century, announced Tuesday, March 17, he will retire as the institution’s chief executive officer when his contract ends in December. McPhee, who has served as MTSU’s leader since January 2001, formally delivered his decision through a letter presented to Board of Trustees Chairman Stephen B. Smith at the end of the president’s report at the conclusion of Tuesday’s trustees meeting at the Miller Education Center. McPhee told trustees that, as a tenured professor, he plans to take a sabbatical to retool and prepare to ultimately return to the faculty…