The 21-year-old spent time on loan at Wrexham last season, and will become Pompey boss Richie Barker's first signing.
"We certainly need to [sign players] in terms of numbers," Barker said after New Year's Day's 2-1 loss at Southend.
"We are scrambling around the development squad. With all due respect to the boys, numbers is an issue."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball