Everton, one of the most successful clubs in English football history, has suffered major injuries to key players throughout its history. These injuries have had a significant impact on the team's performance and have at times led to defeats or even relegation.

One of the most notable examples of this is the injury to defender Phil Jagielka, who was ruled out for six months with a knee ligament tear. This absence meant that Everton struggled defensively and lost several important games, including a crucial match against Arsenal which saw them lose 2-1. The club also struggled to find a replacement for Jagielka, who was one of their best defenders and a key player in the team's defensive structure.

Another example is the injury to striker Romelu Lukaku, who missed several key matches during the 2017-18 season due to a hamstring strain. Despite his return, Everton still struggled offensively and failed to win any of their last four league matches, culminating in a relegation battle. The club also struggled to score goals and relied heavily on substitute strikers to provide goals, further exacerbating their struggles.

These injuries have not only affected Everton's results but have also had a negative impact on the team's morale and confidence. Players who miss key matches can become frustrated and demotivated, leading to poor performances and ultimately causing the team to struggle.

In conclusion, Everton's injuries to key players have been a major blow to the team's performance and have at times led to defeats or even relegation. While some replacements have been made, these injuries have had a lasting impact on the team's success and have required significant changes to the squad. It remains to be seen how Everton will overcome these challenges and bounce back from their current situation.