The 20-year-old becomes Paul Hurst’s fourth new addition of the summer and follows the trend of adding players full of potential.
Jules, who has penned a two-year deal, was well-thought of at the Royals having risen through their academy and is believed to have turned down a new deal in search of first-team football.
The Scottish under-21 international sampled his first taste of senior first-team football last season with a loan spell at Scottish Premiership side Motherwell, where he made 10 appearances.
“We want to show if we can further develop him,” said Hurst of the left-sided centre-back. “He’s signed on with us for a couple of seasons and fits that model of what we’re trying to get – not in every player – but having a younger player that we feel has a lot of assets.
“He probably just needs bits of tweaking to try and get him exposed to first-team football,” he added.
Jules joins Arthur Gnahoua, 24 and Jon Nolan, 25 as young and hungry captures rising up the Football League ranks, while also tying down the futures of 21-year-old Bryn Morris and Shaun Rowley, 20.
The boss added: “If you get too many of the younger players it could be a bit of a risk but we’ve still got experienced players here and it might be that one or two more of those come in.
“I certainly wanted the group overall to be younger, hungrier and have some value for money with potential on the pitch.
“It’s no good having a team full of 30-year-olds, you’re never going to sell a player that way.
“It’s not a prerequisite, we want people saying ‘let’s go down to Shrewsbury, we know they’ve got some good young players there’.”
Hurst said defensively his squad was beginning to take shape.
“There’s still one or two to look at there but at the minute with the lads that are already here, adding Zak into that, with the young lads Robbo (Callum Roberts) and (Ryan) Sears, we’ve got some competition.”