The 26-year-old recently named in the United States' World Cup squad has been squeezed out of the first-team picture at Old Trafford this season following the arrival of Edwin van der Sar.
Howard was limited to just six senior appearances with his only Premiership outing coming against Portsmouth in February.
After arriving from Major League Soccer outfit New York MetroStars in 2003 Howard initially appeared to be the answer to United's long-standing goalkeeping problems.
However high-profile blunders in European games at the end of his first campaign with the club and the start of his second put the U.S. keeper's place at risk.
Despite those problems and his recent omission Sir Alex Ferguson remains a big admirer of a player who has played 77 times for the Red Devils.
And with Van der Sar's contract due to expire in 12 months' time the Red Devils boss has sanctioned a loan move to Goodison Park during which he expects the American to prove he is worthy of reclaiming the United number one jersey again.