Stefan Bradl enters the busiest stage of the Moto2 season with a comfortable lead, but riders are queuing up to challenge him for supremacy at Barcelona.

That was evident two weeks ago at Le Mans when an inspired Marc Marquez charged through the field to take his maiden victory in the Intermediate class, with Yuki Takahashi pushing the German down into third.

Marquez returns home to Spain as the form man. There has been no doubting his speed in the first four races but the 18-year-old has been accident prone so far. Having finally put a clean weekend together in France, the season may now burst into life for Marquez.

Takahashi will also be confident of taking the fight at this weekend's Catalunya GP. This is the venue where he took his first, and so far only, Moto2 victory last year and a repeat would put him firmly in championship contention.

As ever, Julian Simon has been Mr Consistency so far this year. The Mapfre Aspar rider is still searching for his first win in the intermediate class but four top-ten finishes have made him the nearest challenger to Bradl, just 28 points adrift. Having tested at Aragon in between events, Simon will be expecting a strong performance on home soil.

Andrea Iannone is just a point further back and the Italian will surely feel he should be leading the championship at this stage. The Speed Master rider slid out of the lead in Estoril and having secured his best grid slot of the year, did the same on the very first lap at Le Mans.

Barcelona doesn't hold good memories for him either. Victory last year should have been his after qualifying on pole, but a ride through penalty put paid to that and handed 25 points to Takahashi. Like Marquez, there is no doubting his pace, but Iannone's sheer unpredictability will make him one to watch again.

Consistent starts have left Thomas Luthi and Simone Corsi in strong positions as the season approaches the quarter mark. Both riders are also chasing their first Moto2 wins and Luthi will certainly be a threat in qualifying, having started on the front row at every race so far.

There have been contrasting fortunes for the Brits so far, with Bradley Smith excelling in his debut campaign at this level. A puncture put paid to any hopes of points at Le Mans but the Tech 3 rider will be looking to continue his encouraging start to the year.

Scott Redding started the season among the favourites but is still to score a point in 2011. A mixture of bad luck and untimely mistakes has left him playing catch up but it will surely come good for him soon. Kev Coghlan seems to be over the injury problems which hampered him in Portugal and after a solid weekend in France, the Scotsman will hope to move closer to the points in Barcelona.

First practice for the Moto2 Grand Prix of Catalunya starts at 10:10 UK time on Friday morning and The Checkered Flag will have full coverage throughout the weekend.