Kevin Brown and Shaun Lunt have been added as cover to England's squad for Saturday's Gillette Fusion international against France.
The uncapped Huddersfield duo are on standby for the game at Leigh as Danny McGuire and Kevin Sinfield are suffering with knee injuries.
Both McGuire and Sinfield were hurt playing for Leeds in their 28-22 engage Super League win over Wakefield on Friday at Headingley.
They were sent for scans on Sunday to determine the full extent of their injuries and the England management will get the results on Tuesday.
"We'll assess them today and have a look at them in practice tomorrow and make a decision after that," said England coach Steve McNamara.
"We've got three doubts but the two coming in will adequately cover any losses that come our way."
If the Rhinos pair are passed fit, stand-off Brown and hooker Lunt will return to their club to prepare for Friday's Super League game at St Helens.
Injuries have already caused problems for McNamara, who is without Kyle Eastmond for his first match in charge.
The St Helens scrum-half has been ruled out for a month with an ankle injury, while there are also now doubts over his club colleague James Roby.
The hooker went off with concussion during Saints' 27-26 defeat at Hull FC on Friday night. He will have to undergo the mandatory 'head test' later this week to prove his fitness ahead of the mid-season fixture against the French.
"I feel fine now," Roby said on Monday.
"At the time I didn't really know what was going on for about 20 minutes but was fine after the match and I've had no headaches or anything.
"The doctor has checked me over and I just need to do the head test."