The Hoops midfielder was unable to pin down a regular starting berth under former boss Ronny Deila, who signed both him and Gary Mackay-Steven from Dundee United early last year.
When Armstrong did feature, it was often on the left flank but since taking charge at Celtic over the summer, Rodgers has employed the 24-year-old in a preferred central midfield role, where he has thrived.
Armstrong netted Celtic's second of the game in the 3-0 win over Hamilton on Christmas Eve with a 25-yard strike he has "probably not" bettered, before rushing to the technical area to celebrate with Rodgers.
Substitute Moussa Dembele added a third near the end to keep Celtic 14 points clear of Rangers with a game in hand over the Ibrox side.
"I don't really know what to do with my celebration, I just got carried away a little bit," said Armstrong.
"I owe a lot to the manager for everything he has done since he came here for me personally and the team, which is to really enjoy life at Celtic in that central position. I definitely have a lot to thank him for.
"You want to score and I don't care how they go in, as long as somebody is putting the ball in the net.
"But obviously from a personal point of view, scoring goals is always nice to help the team and when they go in like that, it's always that bit nicer."