The Premier League managers who have had contingents of players away on international duty face an anxious few days as the troops return to base.
Damaged limbs are always a danger.
And depending on results, damaged morale can be a problem.
And Arsene Wenger will be feeling as much a sense of unease as anyone.
Just over a year ago, Arsenal went into the autumn international break in reasonable form.
They had lost just once in the Premier League - and that was a close-run affair at home to Chelsea.
They had won at Liverpool, thrashed Southampton 6-1 and launched their Champions League campaign with a 3-1 win over Olympiacos.
Santi Cazorla was looking like the signing of the summer, Lukas Podolski had scored in front of The Kop and Olivier Giroud was adjusting and adapting.
And they had rounded off the programme before the break with an emphatic win at Upton Park which even the most die-hard West Ham fans were admitting was comprehensive and deserved.
What Wenger did not want was any interruption to break the rhythm.
Unfortunately, that is exactly what happened.
Cazorla's form had earned him a call-up by Spain.
Then there were the English, French and German call-ups.
Wenger was rightly concerned.
But the fixture list appeared kind to Arsenal.
The first match after the resumption was away at Norwich - a Norwich team that had endured a nightmare start to the season.
Three points waiting to happen it was assumed.
Norwich capitalised on a mistake by Vito Mannone and the Gunners looked sluggish and out of sorts.
It took them some time to recover.
In the two competitions that matter to Arsenal - the Premier League and the Champions League - Arsenal struggled.
Only one win was registered until mid-November and that came against a Queens Park Rangers team who were down to ten men and were unfortunate to lose 1-0.
There was a reason to be cheerful when the second victory was recorded as Tottenham were beaten 5-2 at The Emirates.
A touch misleading because Tottenham played a man short for most of the game.
The truth is that Arsenal were only able to recover their early season form until the following spring as they clinched fourth place.
Wenger would have appreciated a home fixture when hostilities resume this weekend.
Instead he got Sunderland away ... and the Wearsiders have had a start to the season which has worrying echoes of that endured by Norwich.
If he looks a bit edgy in the next few days, it is understandable.
For him, international breaks have often been a curse and rarely a blessing.