As Euro 2020 progresses, managers, coaches, players and fans will have an eye on the tournament's yellow card policy.
A caution could mean a player is walking a tightrope to avoid suspension, while two yellows could result in him missing an all important fixture.
Which England players are on a yellow card?
A quartet of England players will be walking a tightrope if selected for the Euro 2020 quarter final tie against Ukraine after picking up yellow cards in previous games.
Another booking against Ukraine for any one of the four Three Lions would result in a one-match suspension should England win, meaning they would miss the semi final.
Phil Foden was shown a yellow card against Croatia, in the first match of the Euros, while Harry Maguire, Declan Rice and Kalvin Phillips were all booked against Germany.
The last 16 encounter at Wembley Stadium saw England record an historic 2-0 win over their old rivals and progress into the quarter finals of the 2021 football tournament.
When do yellow cards reset?
The good news is that all bookings are wiped clean after the quarter finals have been played, meaning players who have been cautioned will not carry the yellow card into the semi finals.
It is sure to play another part in Gareth Southgate's thought process as he picks his England team to face Ukraine in the last eight, as he plots the Three Lions' progress at the Euros.
Southgate could decide to rest Maguire and bring Tyrone Mings, who impressed in the opening two group games, back into the fold, while he is not short of options in midfield or attack.
Foden has faced competition from Bukayo Saka, Jack Grealish, Marcus Rashford and Mason Mount in the wide areas in support of the free scoring Raheem Sterling and Harry Kane.
Jordan Henderson, meanwhile, has featured from the subs bench in the centre of midfield.
Which Ukraine players are on a yellow card?
Southgate isn't the only one with food for thought, with his opposing number in the Ukraine dugout, Andriy Shevchenko, weighing up his options ahead of the quarter final.
Four Ukraine players - Artem Dovbyk, Andriy Yarmolenko, Mykola Shaparenko, and Serhiy Sydorchuk - all go into the last eight game against England on a booking.
Do yellow cards carry over into the final?
Under UEFA's tournament rules, a player cannot be banned for the final after picking up two yellow cards during the course of the 2021 Euros.
The slate is cleaned after the quarter finals, meaning anyone going into the quarter finals on a booking who doesn't pick up another caution has that yellow wiped out.
A player can only be suspended for the final if they receive a red card in the semi final.