Eddie Jones is hopeful that back-rower Courtney Lawes will recover from his knee injury in time to start England's clash with South Africa on Saturday week.
Lawes was a late withdrawal from Northampton's matches against Montpellier and Gloucester due to bruising on the joint and had effectively been ruled out of the Springboks clash at Twickenham by his director of rugby Jim Mallinder.
But Jones is optimistic the 27-year-old will be passed fit as England seek to extend their flawless record under the Australian to 10 Tests.
The injury crisis which has thinned Red Rose ranks has accounted for first choice second-rowers Maro Itoje and George Kruis, so Jones can ill-afford to lose another option in the position.
"Courtney's medical situation is ongoing. He probably won't train much this week, if at all. We're cautiously optimistic he'll be all right for the South Africa game," Jones said.
Lawes' Northampton teammate Dylan Hartley faces a challenging week during the five-day training camp in Portugal as the hooker seeks to improve his fitness before leading England against the Springboks.
Hartley has made one start and one replacement appearance since recovering from a back problem and needs to prove to Jones he can get up to speed.
"We'll see if Dylan is ready at the end of the week," Jones said at the squad's hotel in Vilamoura, Portugal.
"We'll have a good week's training so we'll know where every player is in terms of how ready they are to play international rugby."
England have been robbed by injury of 10 players for the entire series that continues with fixtures against Fiji and Argentina and concludes against Australia.
"Rugby is a physical, contact game. England pride themselves on having depth so this is a great opportunity to show how much depth we've got," Jones said.
"We've got an absolute plethora of injuries so we're trying to work out who is going to be right and who isn't.
"But we'll get there. What I do know is that we'll have a fit 23 players who are ready to beat South Africa."
