Northampton's weekend opponents saw manager Paul Cook leave for League Two rivals Chesterfield recently, bringing in former Blackburn player Leam Richardson as his replacement.
And Richardson has moved quickly to draft in his former Ewood Park colleague, until January initially.
"Leam has come in as the manager and asked me to come along and play some games and do a little bit in a coaching role," Beattie told BBC Radio Lancashire.
Aidy Boothroyd meanwhile told BBC Radio Northampton: "It'll be a tough place to go. We've just got to lick our wounds and get on with it."
Source: Cobblers Mad