Is this the stat that shows why Chelsea are so lucky with injuries?

Jose Mourinho is the most prolific manager in Premier League history to use substitutions.

The Blues have been extremely fortunate with injuries this season, with Diego Costa and Loic Remy the only first-team members to miss extended periods of play.

And of that pair, Costa arrived at the club injured, and Remy has a history of being susceptible to injury, making the fitness work of the West London club seem impressive.

It has been largely thanks to Jose Mourinho’s ability to pick a consistent starting XI that has led Chelsea to the top of the Premier League table, whilst his rivals have had to rotate with squads being hit heavily. Mourinho knows his strongest XI and has stuck to it for every possible game, and the benefits are being felt amongst the team.

The coach is well praised for his squad management ability and decision to not rotate unnecessarily, but there is a surprising stat that shows Mourinho’s real squad policy.

As shown on the official Premier League website, Mourinho is the most prolific manager at making substitutions in Premier League history, with a rate of 2.93 changes made per game.

In 179 matches, the coach has made 524 substitutions, with Manchester City boss Manuel Pellegrini in second place, with a rate of 2.92 - although that is only from 59 games.

Rather than rotate his squad before games, Mourinho waits until his strongest XI has killed games off before resting the players who need it by taking them off the field of play.

The Portuguese coach has also built a reputation for making substitutions early into games for tactical reasons, if he can see his gameplan is not working. Sometimes pulling people off the field of play inside the first-half - or once using all three substitutions at half-time in an FA Cup defeat to Newcastle - he has become a master of the art of utilising his full squad at the perfect time.

Any sign on injury to a player on the field is responded with an almost immediate withdrawal, and Mourinho’s willingness to change things during games has played a key factor in keeping his squad at full fitness for the duration of the season.

Mourinho still has someway to go to catching up with Ex-Manchester United boss Alex Ferguson, who holds the record for most substitutions in the top flight. In his 810 game Premier League career, Ferguson made 1777 substitutions, at a rate of 2.19 per game. However, Arsenal head coach Arsene Wenger could overtake that tally this season, with the Frenchman just 22 subs behind Ferguson’s record.

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