When you have hurt yourself in a game, you need to take the time off to recover.
Many dedicated players like Manu Tuilagi would have still continued with the injury they sustained if given a chance. However that would only jeopardize their health and their future in professional rugby. For these reasons Manu Tuilagi was kept out of the tour of England with Australia. When Leicester suffered a defeat at the hands of Saracens in the semi finals of the Premiership, Manu was found to be limping out of the field. He was diagnosed with injury to the hamstring. As a result the Center ruled out his participation in the forthcoming tour.
Indeed, not every player gets to be chosen to be part of national tour. However, as the saying goes, one needs to rest and revive in order to play again. The same is true for Manu who might have missed out the opportunity to play for England against Australia but that would not have been possible with a hamstring injury that occurred so close to the tour. As it is with joint and muscle problems, one tends to take few months to recover from such ailments.
There is physical therapy required under close supervision and hence, being out on the field with an injured hamstring would be a suicidal decision. Eddie Jones had chosen him to be center player for the team. However, with a hamstring tear, Manu looks at six weeks of recovery time. Eddie Jones voiced his regret of not getting to have Manu on the team. It also raises questions about the suitability of an artificial turf. Many players are found to be more prone to injuries when they play on artificial turf like Manu who has been plagued with problems in his hamstring and groin for over two years now.