The winger has been linked with a loan move to Inter but the Spurs boss believes the 21-year-old needs more time to adapt to the Premier League.
The 21-year-old, who arrived at White Hart Lane in a 30 million euro deal from Roma in August, has struggled to secure a regular first-team place this season and has started just three games in the Premier League.
Inter has been linked with a temporary deal for the Argentina international but, as Goal UK reported on Thursday, Tottenham is adamant that the winger will not be permitted to leave the club this month.
"He won't be leaving on loan in this transfer window. He has a big future here, absolutely," Sherwood said. "We know what a talented player Erik is. We also understand that players need time to settle. He needs time to acclimatize to this country. He doesn't speak English and he isn't used to the pace of the games, especially over the Christmas period when they come thick and fast.
"He is not 100 percent fit, either. He's still feeling fatigued in one of his thighs so we were very cautious with him. We are going to take it nice and steady with him. I really want to put him on the stage when he's ready to perform, rather than let people judge him when he's half-cocked."