The defender is poised for further surgery on a knee problem that has seen him sidelined since March.
"Kelvin's a warrior but if he doesn't think it's quite right, it's important we get him looked after and sorted," Boothroyd told BBC Radio Northampton.
The Town boss has Darren Purse on trial at the club as potential cover and said he was pleased with the performance all of the players looking to earn a Cobblers deal in Tuesday night's win at Cogenhoe.
Lateef Elford-Alliyu made the headlines on Tuesday with four goals as he aims to impress Boothroyd enough to be offered a contract while combative Irish midfielder Gary Deegan is also training with the club.