Smith's three injury-affected years in Manchester have seen him become a favourite with the fans, but Ferguson seems on the look-out for re-inforcements up front.
Boro are one of a host of clubs to have been planning a bid with the Teessiders boss Gareth Southgate having reportedly stolen a march with a £6m offer.
Tottenham, Newcastle, Portsmouth and Sunderland are among the other clubs who are believed to be eyeing the situation after Smith's agent urged the Red Devils to assure the England forward he has a future at the club.
Black told BBC Radio Five Live: "Obviously, you're going to have some question marks in your head as to where that leaves you. I think if you're definitely not wanted, you need to be told that."
But the silence on Smith's situation has been deafening and the club appear unwilling to comment on the reports of a deal with Boro.