Roy Hodgson will give Jack Wilshere and Jordan Henderson as much time as possible to prove their fitness ahead of Euro 2016.
England manager Hodgson opted to name a 26-man provisional squad for the tournament in France, largely in order to run the rule over Wilshere and Henderson.
Arsenal midfielder Wilshere only featured in the last three Premier League matches of the season after enduring another injury-hit campaign due to a broken leg.
Liverpool captain Henderson missed 10 matches with a knee injury sustained against Borussia Dortmund in March and, although he came off the bench against West Brom last weekend, he was an unused substitute in the Europa League final defeat to Sevilla on Wednesday.
Henderson subsequently reported for England duty early to continue his recovery, and Hodgson says he will not make a hasty decision on his and Wilshere's involvement in France.
"The mere fact Henderson is in contention is an enormous bonus because when the injury occurred, we were told to work on the basis that it would keep him out of the Euros because it would take a longer recovery time," Hodgson told a news conference.
"He, alongside Jack, are the reasons we have extended our squad from the usual 23 to 26 because we do need to assess them.
"We do need to be sure that if we are going to select them, they will be the Jordan Henderson and the Jack Wilshere that we know and not players that are recovering to be that player again.
"We have to be satisfied with them. An international tournament puts an awful of demand on a player physically."
Despite the competition for places in England's Euros squad, Hodgson insists there has been no extra edge in training.
"Training sessions are always intense, competitive and the tempo is almost always high," he added.
"The level of skill I see is high. I'm pleased with the sessions in terms of quality, it's not down to extra edge brought about by people fighting each other for positions."
England face warm-up friendlies against Turkey, Australia and Portugal before playing their tournament opener against Russia in Marseille on June 11.
