Jack Wilshere was ready to make a late entrance against Watford on Saturday.
In fact, the man he was due to replace - Alex Iwobi - was already leaving the pitch.
Moments later, Rob Holding came on for Laurent Koscielny instead. After the game, Arsene Wenger explained why.
“I wanted to take Iwobi off and they told me that Koscielny had to come off because of his calf,” said the boss.
“When I wanted to bring Jack on for Iwobi, it was our last sub and Koscielny could not go on, so I had to change Koscielny and bring a centre back on. That’s what happened.”