This cliche is often used in football to talk about how much effort a player gives in the match. ‘A shift’ refers to a person’s working time, particularly when talking about physical work. ‘To put in’ means to do, so to put a shift in means to work hard. Football pundits, commentators and managers use this phrase to say that a player has tried very hard for the team. To put a shift in, however, doesn’t mean the player was particularly skillful. It is often used to highlight the fact that another player didn’t put a shift in, didn’t try hard. You can also say, put in a shift.
For example: Aaron Ramsey praises Arsenal for putting in a good shift after Saturday’s 2-0 win at Sunderland. For example: Balotelli put in a decent shift, but still no Premier League goal.