Montague said: “Sometimes, in the transfer market, an opportunity presents itself which is too good to pass up – and the board are in agreement that this is one of those instances.
“Lucas is an outstanding young defender who has huge potential to improve over the duration of his contract, so we’re very excited to bring him to Meadow Lane.
“He has already proven himself highly capable at League One level, with his maturity and dependability belying his young age.
“He’s fantastic in the air, comfortable on the ball and, while perfectly suited to the right centre back role, is capable of playing anywhere across the back three.
“Lucas is coming to the end of a successful rehabilitation from an injury he experienced last season and, with Matty Platt, Jacob Bedeau and Robbie Cundy settling in nicely, Rod McDonald nearing a return and Lewis Macari having a strong start to the season, we can ensure Lucas takes the time he needs to get up to speed and show his quality when ready.
“This is very much a signing made with the long-term in mind – and it doesn’t affect our plans to strengthen other areas of the squad before the transfer window closes.”