With Rio Ferdinand a certain starter in Tuesday's Champions League quarter-final second-leg with Chelsea, Smalling knows he will be dumped back onto the substitutes' bench.
It might be a feeling the 21-year-old gets used to over the coming weeks as the pressure and intensity increases over the final weeks of the campaign.
But Vidic insists Smalling's long-term future is secure.
"Chris has done very well," the Serbian told United Review. "He didn't have any trouble stepping into the team and he showed everybody how good a player he is.
"It has been a great season for him and he has a big future in front of him. He is only 21, so it is a massive achievement for him to have played so many games at his age for this club."
Source: PA
Source: PA