Peter Shilton thinks Rooney should have retired after the Euros. I agree. I'm surprised Mourinho didn't nudge him in that direction. He'd be far more effective for Utd if he got a break every international week.
Rooney is on a hiding to nothing playing for England. He's not going to play centre forward; he shouldn't play no.10 ahead of the younger and more dynamic Alli; he's not a midfielder - although England do lack a playmaker/continuity player so it can't be claimed that he's keeping a better option out of that role. His strengths in the past have been his willingness to receive the ball, his running, his pace, his eye for goal and his technical ability (although the latter is not saying much when compared to most other England players he's played with). He has shown his ability for Utd regularly (aided by better players around him) and for England spasmodically, but now his attributes are fading with age. He would be a better player if he was used more sparingly - and that means limiting his commitments to club football only.
International football is a strange beast these days. There are so many teams and so many games. Most countries have a group of players who play in one or more of the major leagues so their opponents are well known to them from the many club games they play. All teams are now well organised and play tactically, carrying out a well drilled plan. The emphasis is on being strong defensively. There is little chance for skill to shine. And skilful players are further hampered by tournament football being at the end of 60+ game club seasons plus friendly and/or qualifying international games, pre-season tours around the world etc, so there is the likelihood of fatigue, injury and sometimes indifference, as well as the burden of expectation. The Euros didn't produce top quality football from top players - it was memorable for teams on an adrenalin high punching above their weight and Portugal riding their luck. It seems to be literally the survival of the fittest - so better perhaps for Sam to pick younger legs in all positions and to follow these same methods (which he's done himself at club level anyway) of organised, well drilled defence and uninspiring attack aiming for a 1-0 win.