Chelsea boss Jose Mourinho this week accused his title rivals of trying to buy the Premier League. The man is no stranger to playing mind games with his fellow managers, though his apparent frustration in the transfer market so far this summer raises some interesting questions. Those who joined him in the top four last season appear to have improved their teams, and each manager has a shed load of title winning experience. Could this be the most exciting season yet?

What a difference a year makes. After Manchester City reclaimed their throne in 2014, it was Jose Mourinho’s Chelsea who appeared to emerge as early favourites after some typically astute signings rectified the problems they suffered in the season before. Diego Costa and Cesc Fabregas arrived, along with Filipe Luis, and Thibaut Courtois finally returned from his loan spell. The Blues looked to be the strongest side in the league, a mantle to which they lived up to.

However, a year on – Chelsea do not look as strong. Radamel Falcao and Asmir Begovic have arrived in West London, with Everton defender John Stones reported to be the next through the door. Though top quality players and the envy of many other outfits, they appear to have been brought to the club as squad options. We can obviously expect the defending champions to challenge for top spot, but their lack of activity in the market raises some interesting questions. It is important never to write off the scheming Portuguese gaffer, but have Chelsea allowed their rivals to close the gap? Could this season finally see a four horse race?

Manchester City are eager to reclaim a title they have won twice in three years. A blockbuster move has seen England winger and the 2014 incumbent of the prestigious Europe’s Golden Boy award, Raheem Sterling, arrive at the Etihad. The former Liverpool man lines up with Sergio Aguero and David Silva, in perhaps the most exciting front line in the league. It would seem silly to suggest that after last season’s showing that City are now on the same level as their London rivals, but we must remember they won the league in 2014.

Should manager Manuel Pellegrini be able to coax captain Vincent Kompany and midfield man Yaya Toure back to their stunning best, the 2014 title winners have perhaps the strongest spine in the league. Sterling adds an injection of pace and unpredictably to a front line boasting the guile of Silva and last season’s top scorer Aguero. City can edge ever closer to top spot, it seems.

Chelsea legend Petr Cech has move across London to Arsenal in another blockbuster deal. Much has been made of the move, with Arsenal now significantly strengthened between the sticks. Even Blues captain John Terry has waxed lyrical over the importance of his former team-mate, believing he could save them ’12-15 points’. The Gunners may still lack a world-class centre forward, but Alexis Sanchez and Mesut Ozil top the list in a midfield brimming with quality.

Olivier Giroud is a good striker, and Theo Walcott’s transition to an out and out forward may well have a profound impact a side who have struggled to seriously maintain a title challenge. The core of Arsenal’s squad has been growing together since 2012, and now looks to be a very well-oiled machine. With time still available to Arsene Wenger in the transfer window, the FA Cup Champions could be ready to arise as league victors.

Now we have Manchester United. So much has been written about the side over the past two years, but this team appears to be pulling out of the post-Sir Alex transition. In Louis van Gaal they have a manager who has won titles wherever he has been, and their activity in the market this summer has been excellent. With big deals still on the horizon, Red Devils fans can be quietly optimistic about their title chances. It may seem like a rather big leap, but the money the club have spent and Van Gaal’s experience should surely count for something. Should a title victory prove to be a step too far, they will at least be far more of a threat than last year.

In Wayne Rooney they possess a centre-forward of a quality much higher than Arsenal’s. Diego Costa and Sergio Aguero were excellent last year, but both are injury prone and both Chelsea and City’s back up options are a major step down. England captain Rooney is nowhere near as injury prone as his golden boot rivals, and can largely be relied upon for a whole season.

Chelsea may well defend their title this year, they have the resources to do so. However, their lack of activity in the transfer window has allowed their would-be challengers to close the gap. For the first time in years, four sides have a feasible chance of winning the top prize in English football. This could be the best season yet.