There was a time perhaps three or four years ago when the Premier League seemed to split into two groups. There was the top seven, who would contest the European places, and there was the bottom 13 whose first thought each season was simply to avoid relegation. That, perhaps, has changed now.

A clear top six remains, probably itself with a subdivision into a top four, then Liverpool and Tottenham. The bottom chunk has now subdivided, creating probably seven or eight teams who should be relatively safe, and a scrap for the three relegation places between six or seven teams.

Such is the gulf between Premier League and Championship that the three promoted sides will immediately be under pressure. Leicester City and Sunderland, having produced remarkable late surges last season to avoid the drop, must anticipate another season of struggle. Aston Villa and Newcastle United also found themselves in the dogfight last season and both could get sucked in again.

Two of the promoted sides, Bournemouth and Norwich City, have exciting young British managers. Eddie Howe is only 37 years old and played for Bournemouth between 1994 and 2002. The young manager returned after two years for another three seasons and became manager in December 2008 when Bournemouth was adrift at the bottom of League Two after beginning the season with a 17-point penalty for going into administration. He had a disappointing year away at Burnley, but that aside, Howe has charted Bournemouth's extraordinary path to reach the Premier League for the first time in its history.

Dean Court, or the Vitality Stadium as it's more properly now known, has a capacity of just 12,000. While that obviously poses problems in the longer term, it also gives some indication of just how far the club has come. Cynics will point out that Bournemouth's rise has been possible only because of investment from the Russian petrochemicals tycoon Maxim Demin, who has part-owned the club since 2011, but by the standards of oligarchs he is small fry and investment this summer has been minimal. Left back Tyrone Mings has been bought from Ipswich for $12 million but otherwise there have been four free transfers and a loan. Christian Atsu offers penetration on the right, but much will depend on whether 37-year-old centerback Sylvain Distin can rediscover his form or whether, as seemed the case at Everton last year, age has caught up with him.

Norwich City is in a similar position. Alex Neil is 34 and only took over Norwich in January, having impressed in taking Hamilton Academical to promotion to the Scottish Premier League. He has great promise, but this is a limited squad. Of the 11 that started the playoff final against Middlesbrough last season, 10 had been in the squad relegated from the Premier League the previous year. The club has added Robbie Brady, relegated with Hull last season, right back Andrew Wisdom from Liverpool (on loan) and Graham Dorrans and Youssouf Mulumbu, midfielders who didn't fit Tony Pulis' system at West Bromwich Albion.

The worry for Howe and Neil is that they end up, like so many other promising British talents, having their reputations ruined by a season of toil. As Howe has pointed out, though, the example of Swansea City shows what a small Premier League club can achieve.

The other promoted side, Watford, have a very different model. The club is owned by the Pozzo family, which also owns Granada and Udinese. So far, Udinese has been the priority with the other sides essentially development clubs; the revenues on offer in the Premier League may change that. The Pozzos are very Italian in approach; they sack managers frequently and, given Quique Sanchez-Flores, appointed in the summer to replace Slavisa Jokanovic, has no experience in English football, he could easily be the first Premier Lerague manager dismissed. The real worry for Watford is its record against decent side in the Championship last season, as the club collected three wins in 14 games against the other members of the top eight.

Leicester City also surprisingly got rid of its manager in the summer, Nigel Pearson, parting ways with the club shortly after his son was sacked following an incident on a club tour of Thailand. How related the incidents were, however, remain unclear. Pearson was combustible and awkward but ultimately effective. Italian manager, Claudio Ranieri, now 63, has a big act to follow.

Sunderland, after two remarkable escapes in a row, would love a quiet season. The summer has been gently encouraging as the squad has been rationalized, but there still seems a general lack of pace. There was evidence of the defensive discipline Dick Advocaat instilled towards the end of the season in the 1-0 win over Hannover 96 on Saturday. This is still a club looking anxiously down rather than expectantly up.

The arrival of Tim Sherwood last February seemed to have cured Aston Villa's ills. The question remains how effective Sherwood can be when the initial boost provided by his ebullience has worn off. The dismal performance in the FA Cup final and the sales of Christian Benteke and Fabian Delph have only added to the concerns. After a false start at Tottenham, this is the real test of Sherwood's managerial nous.

And then there's Newcastle, which has added intelligently to an already decent squad, whose ownership seems mystifyingly drawn to self-destructiveness. The appointment of Steve McClaren, at least, should offer stability and experience at the top.

Of course it's possible that bad start could drag a side like West Brom or Crystal Palace, perhaps even West Ham United if the Europa League proves too much of a distraction, into the mix. Either way, this season's relegation battle will be interesting to say the least.