Chelsea face a stern test to defend their Premier League crown next season as their rivals are set to invest heavily to compete next season, whilst the Blues have a disappointing record in the transfer market following a season where they have finished successfully.

Blues boss Antonio Conte has an array of areas in his squad that need to be improved, as the West London giants need significant depth between the sticks, in central defence, in the wide areas of their back-line, in central midfield and up front.

Crucially though, the Blues also have significant question marks hanging over the heads of key players as the likes of Thibaut Courtois, Diego Costa, Cesar Azpilicueta and Eden Hazard have all been linked with summer moves to some of Europe’s biggest sides.

Courtois and Hazard have both been heavily linked with moves to Spanish giants Real Madrid, whilst Azpilicueta has been reported to be one of the prime targets for new Barcelona boss Ernesto Valverde- who’s looking to shore-up his defensive ranks.

Should Chelsea lose any of that starring quartet, then their chances of success next season will be significantly less- and the Blues’ huge summer would prove to be even more testing, as they’d need to invest significantly in more areas.

At the current rate, Chelsea need around four or five signings to boast the depth needed to compete in both the Premier League and Champions League next season- which will be difficult to secure in one months window and an array of new players may struggle to settle.

Should key-players leave, the number of signings needed by Chelsea would increase significantly and, crucially, the players coming in would have to settle into the first-team fold immediately and that would be difficult with an array of new faces- as showed by West Ham last season.

Both Manchester sides are set to invest heavily this summer and they will be difficult to compete with, whilst Tottenham, Arsenal and Liverpool will continue to push for glory- which doesn’t give Chelsea much room for mistakes.

In the current decade of the Premier League era, the 2010’s, no side has successfully defended their Premier League title and Chelsea will need to be at their best to have any hope of breaking that trend and moving forward under Conte.

For that to happen though, Chelsea need to keep their key players at the club and must also make significant signings of their own to make a statement of intent to the rest of the Premier League- and selling key-players would not be the right message.