The Brazilian midfielder was left out of Sherwood's squad on Saturday as Tottenham recorded a 3-1 home victory over relegation-threatened Fulham.
Christian Eriksen inspired Spurs with two assists, as Paulinho, Harry Kane and Younes Kaboul got on the scoresheet.
A frustrated Sandro, who has not featured in the Premier League for more than a month, took to Twitter before kick-off, confirming that his absence was not due to injury.
"Good morning Guys, just to let you know that i'm not injured ! Hope that we can win the game today," read a tweet from his official account.
When asked about Sandro's comments on social media after the game, Sherwood told BT Sport: "What he's stating there is correct. I don't think he's good enough to be in the side at the moment.
"He's got his own reasons for doing it (explaining his absence on Twitter) and he's got a good following here.
"I like Sandro, but at the end of the day he has to work hard to get back in the side. At the moment, he's not good enough to be in the side."
Following Sherwood's televised interview, Sandro laughed off the criticism from his boss, tweeting: "Lol lol lol ..."
Sherwood took satisfaction from Tottenham's victory over Fulham, stating "it's all about points at this stage of the season".
The 45-year-old also remained relaxed regarding further speculation over his future at White Hart Lane.
Asked if he is convinced he will be in charge of Tottenham at the start of next season, he added: "I'm not convinced; I'm not unconvinced.
"I'm not shocked by the speculation, but I'm shocked it's only one manager linked today.
"You take it on the chin. At the end of the day the club have decided not to say anything about that and I can't comment. It's a privilege to manage this football club and the future looks good for Tottenham."
