22-year-old Southampton academy product Hoskins has been on trial with Town throughout the summer and now gets his chance to get more regular senior football under his belt and challenge for a spot in Chris Wilder's starting XI.
Fellow trialist Rod McDonald signed a permanent deal recently and impressed in Friday's final warm-up match, a 3-0 win away to Sheffield FC.
That game also saw Ricky Holmes on the scoresheet, the ex-Pompey man set to be a crucial part of Wilder's plans for the new campaign.
Toney was reported to have had a medical at Newcastle last week but the deal has yet to be confirmed for the 19-year-old striker who has 53 league appearances under his belt for Northampton, over half of those as a substitute.