Armstrong has been gradually emerging as a sought after forward in England following a good season at Blackburn where he scored 28 goals in the Championship for a side that finished 15th in the league table.
Several clubs in the Premier League and the Championship are interested in snaring him away from the Championship outfit.
West Ham and Fulham have been tipped to be the favourites to sign him and he has also been linked with a move to Brighton and Everton.
Norwich are also believed to be interested in the forward but it has been claimed that Blackburn have to recalibrate their asking price for the Canaries to sign him.
Blackburn are said to be holding out for a fee of £25m before agreeing to sell Armstrong this summer.
And while back in the Premier League, Norwich are not known for being big spenders and will not fork out such sums for the forward.
Blackburn are banking on several clubs joining the auction for Armstrong and sore his price up in the coming weeks.
