The 22-year-old shone for his country at the World Cup in South Africa over the summer, leading many clubs to cast an envious glance in the direction of the Italian team before baulking at the asking price.
But with no club willing to take a gamble on Sanchez during the transfer window, Fergie has confirmed he is still tracking the progress of a player who had previously claimed it would be his "dream" to play for the Red Devils.
"We have looked at Sanchez and he has impressed us," Ferguson said, according to the News of the World on Sunday. "As have other players.
"He has had very good games and is an interesting project. We have gathered some background, as with other footballers at his level, but nothing more than this - for the moment."
United were reportedly looking at Sanchez as a possible replacement for the Real Madrid-bound Cristiano Ronaldo last summer, but Fergie swooped for Antonio Valencia from Wigan instead.
The Reds' pursuit of Sanchez is not Ferguson's first foray into the Chilean market. Back in 1998, the United boss chased the £12-million signature of then River Plate striker Marcelo Salas only to be outbid by Italian giants Lazio.
"We have watched some Chileans in the past," he recalled.
"The most interesting case was that of Salas, who had a brilliant World Cup but he was at Lazio. We would have liked to have had him."
Ferguson will be keen to avoid the Salas situation happening again with Sanchez, who has the best part of three-years left on his current contract.
By James Martini
