I was reading the press release for the recent test firing of the RS-25 engine No. 2059 at Stennis Space Center and I came across the quote:
The next time rocket engine No. 2059 fires for that length of time, it will be carrying humans on their first deep-space mission in more than 45 years.
To me this implies that the next time this engine will be used is in around 8 (maybe more) years time when they use SLS to launch astronauts on the Asteroid Redirect Mission (ARM).
Why is there such a delay in using this engine (which has flown several Shuttle missions before) again? Or is it an incorrect statement that they have made in this press release?