England have received a significant injury boost ahead of their Six Nations opener against Italy after Maro Itoje, Mike Brown and Chris Robshaw were passed fit to play.
The trio had all previously been rated doubtful, but returned to training this week and have been given the all-clear for the match in Rome on February 4.
Itoje, who has been battling back from breaking his jaw in two places in December, returned to action for Saracens at the beginning of the month.
Speaking at England's warm-weather training camp in Portugal, the lock told Sky Sports: "Truly and honestly there are two things that I am focusing on. The first thing is getting my body right to be able to participate.
"The second thing is helping the team to best prepare to play Italy. These are the only two things in my head that I want to get right for the next two weeks."
Full-back Brown had been suffering with blurred vision, while a back injury has been troubling Robshaw.
Of the 34 players called up to the squad, only Zach Mercer has dropped out of contention because of a viral infection.
"It has been a great turnaround," said Jones. "Our medical and strength and conditioning staff have done a great job.
"Chris Robshaw, Maro and Mike Brown all did some return-to-play stuff on Monday and looked pretty good.
"Mercer has got a bit of a chest infection but should be alright to train on Wednesday."
When asked about the training camp in Portugal, Jones said: "It was probably one of the best training weeks we've had in Portugal.
"We changed the programme a little bit - we felt the players needed something a bit different.
"We took away a lot of physical and mental stress at the start of the week, freshened them up and then we had a really good end. We trained fast, with skill and good execution."