The 22-year-old missed the Blades' defeat at Ipswich on Saturday and will not take part in Speed's first match as Wales boss against the Republic of Ireland in Dublin on Tuesday.
But young Blades forward Jordan Slew has been called up into the England Under-19 squad to play Germany in Chesterfield on the same night.
Slew, 18, has twice stepped off the substitutes' bench for the Blades' first team this season, and has been drafted in as a replacement for Southampton's Alex Chamberlain, who has been promoted to the England Under-21 squad.
Source: PA
Source: PA