The 21-year-old striker has thrived at Blackburn Rovers since joining the League One club in January.
But with two years remaining on his Magpies contract, the U20 World Cup winner plans on trying to break into Rafa Benitez's first-team.
"Obviously [Newcastle are] concentrating on the Premier League which is a massive thing so hopefully they can stay up," Armstrong told Sky Sports.
"I keep in contact with the Under-23s coach now and then but I'm focused more on getting my head down and doing well for Blackburn.
"It's been hard to get to a game this season but I've got a lot of good friends there and I always check the results because I'm still a massive fan.
"The plan is to go back in the summer and assess the situation because I've still got two years left on my contract."