It is nice vindication for Armstrong, who worked with Dave Wannstedt in Chicago and got his share of criticism after succeeding the highly successful Mike Westhoff, who joined the Jets after a personality clash with Wannstedt.
Earlier this week, the Dolphins announced the hiring of Derek Dooley, Will Muschamp and Bobby Williams, who all were on Nick Saban's staff at LSU.
Foerster became the fourth coach from last year's staff, not including Wannstedt, to leave following Jim Bates' announcement that he would not come back. In early January, Bernie Parmalee and Bill Lewis both accepted offers to join Charlie Weis' staff at Notre Dame.
Foerster, who spent one season as offensive coordinator with the Dolphins, took a job as offensive line coach with the Ravens and he also was named assistant head coach to Brian Billick.
It is also believed that Marc Trestman already has been told he would not be retained, although no official announcement has been made.
Among the other assistants from last year, Bob Sanders interviewed for a job in Jacksonville but lost out when the Jaguars hired someone else.
The other assistants in limbo include Clarence Brooks (defensive line), Joel Collier (running backs), Judd Garrett (offensive quality control/receivers), Glenn Pires (assistant defensive line), Jerry Sullivan (wide receivers), Tony Wise (offensive line) and Jeff Dellenbach (fellowship coach-offense/special teams).
Among those, Brooks and Sullivan might be the most likely to return.