They were the two changes made to the side by PNE boss Ryan Lowe from last Saturday's 1-1 draw with Birmingham CIty.
Ched Evans and Greg Cunningham were the players to make way, the pair moving to the bench.
It is likely that Barkhuizen will play at left wing-back, with Brad Potts staying on the right.
Sinclair's start was his first since the Blackpool defeat in October, with the former Celtic man having made his 500th career appearance as a late substitute on Saturday.
Missing from the Sheffield United squad was former PNE defender Ben Davies who has tested positive for Covid.
PNE: Iversen, van den Berg, Bauer, Hughes, Whiteman, Potts, Browne, Johnson, Barkhuizen, Riis, Sinclair. Subs: Ripley, Lindsay, Cunningham, Rafferty, McCann, Maguire, Evans.
Sheffield United: Foderingham, Basham, Egan. Robinson, Bogle, Norwood, Hourihane, Stevens, Ndiaye, Brewster, Sharp. Subs: Eastwood, Berge, Burke, McGoldrick, Slater, Norrington-Davies, Gordon.
Referee: David Webb (County Durham)