The Lyon flanker leads a matchday squad drawn from nine different nations with more than 700 international caps between them.
Munster lock Donncha O'Callaghan - making his first appearance in the black and white jersey - heads the squad cap count with 94 for Ireland and four Test appearances for the British & Irish Lions.
Ulster's Roger Wilson is also poised to make his Barbarians debut having been named among the replacements.
Head coach Dean Ryan has named a physical forward pack featuring powerful Georgia number 8 Mamuka Gorgodze, and an exciting backs division that includes New Zealand wings Joe Rokocoko (Bayonne) and Hosea Gear (Toulouse). Clermont Auvergne out-half Brock James is the only uncapped player in the line-up.
"Juan Manuel Leguizamon commands respect as a player, he's led the Pumas in Tests and he'll do an excellent job throughout this week and at Twickenham on Sunday," said Ryan.
"It's a privilege to work with such an experienced and talented group, and in the short time we've been together they've shown how committed they are to delivering a first-class performance.
"The Barbarians is a special entity in the way it brings together outstanding players from all corners of the rugby world but ultimately we have to deliver on the pitch and that is our aim."
There are two late changes to the squad with tighthead prop Davit Kubriashvili (Stade Francais) coming in for injured fellow Georgian Davit Zirakashvili (Clermont), while All Black Anthony Tuitavake (Montpellier) replaces Australia's James O'Connor (London Irish).
Tickets to England XV v Barbarians, priced from £25 for adults (£10 juniors), are available from Ticketmaster on 0844 847 2492 or from the RFU ticketing site.
BARBARIANS (v England XV): Juan Martin Hernandez (Racing Metro 92/Argentina); Joe Rokocoko (Bayonne/New Zealand), Rene Ranger (Montpellier/New Zealand), Benson Stanley (Clermont Auvergne/New Zealand), Hosea Gear (Toulouse/New Zealand); Brock James (Clermont Auvergne), Jimmy Cowan (Gloucester/New Zealand); Sona Taumalolo (Perpignan/Tonga), Ti'i Paulo (Clermont Auvergne/Samoa), Davit Kubriashvili (Stade Francais/Georgia), Donncha O'Callaghan (Munster/Ireland), Juandre Kruger (Racing Metro 92/South Africa), Juan Manuel Leguizamon (Lyon/Argentina) (capt), Alexandre Lapandry (Clermont Auvergne/France), Mamuka Gorgodze (Montpellier/Georgia).
Replacements: Andrew Hore (Maniototo/New Zealand), Julien Brugnaut (Racing Metro 92/France), Nahuel Lobo (Montpellier/Argentina), Joe Tekori (Toulouse/Samoa), Roger Wilson (Ulster/Ireland), Tomas Cubelli (Belgrano/Argentina), Francois Trinh-Duc (Montpellier/France), Anthony Tuitavake (Montpellier/New Zealand).