The England national football team's midfielder Declan Rice has been managing nerve pain in a hamstring since Christmas, sparking concern when he was forced off in the 72nd minute of the 4-2 World Cup win against Croatia. Rice described his substitution as 'smart' and said he would be fighting fit for England's second group game against Ghana in Boston on Tuesday. The problem relates to the upper hamstring, with the pain radiating into his lower back. England began a hot-weather acclimatisation camp in Florida at the start of June and know the heat and humidity in North America are among the major challenges. Thomas Tuchel has reassured the players that they have the conditioning to cope with the heat. Rice also talked about the fitness worries that cling to Bukayo Saka, his Arsenal and England teammate, who has been managing an achilles problem for some time. Saka was fit enough to play only as a 72nd-minute substitute against Croatia and is not expected to be ready to start against Ghana. Noni Madueke is likely to continue on the right wing. Rice has played 63 matches this season, 55 for Arsenal and eight for England, and said 'it's an obscene amount of games'. The England national football team's players have been conditioning to adapt to the heat, with Rice saying 'the heat's going to dictate our playing style in spells'. The Croatia game was played in Dallas's domed, air-conditioned stadium, where the temperature was set at 22C. Happily, it is forecast to be something similar in Boston's open-air stadium for the 4pm local kick-off. Rice said 'I'm ready and fit, raring to go' for the Ghana match. The England national football team's manager Thomas Tuchel has been clear with the players that they have the strength and power to outrun and outplay teams with their strength. Rice said 'Bukayo will impact this tournament' and that 'it's really good the way we're managing him'. The England national football team will face Ghana in Boston on Tuesday, with Rice and Saka's fitness being closely monitored.