It's going to be very difficult for the action on the circuit in 2010 to equal the chaos that was the Formula One offseason.

In the span of just around four months, we saw the all-time winningest F1 driver announce his historic comeback, the reigning F1 champ leave his post to join another team, a former world champion -- Kimi Raikkonen -- leave the sport altogether, a points system modified and then tweaked again, an in-race refueling ban announced, the addition of several newcomers (as well as the subtraction of USF1) and 16 drivers debuting with a new team for 2010.

Let's start with Jenson Button.

The 2009 F1 champion left Brawn GP to join McLaren and 2008 champion Lewis Hamilton. It's certainly not the first time a driver has left his team for another squad immediately following a championship season.

Since 1980, the defending champion has left his team following the season eight different times, including Button. Alain Prost left Williams in 1993 but retired, while Nigel Mansell departed for CART following his 1992 championship. Fernando Alonso was the most recent to do it, finishing a single point behind champion Kimi Raikkonen in 2007 after leaving Renault following his title-winning season of 2006.

Other drivers have had varying success; Damon Hill struggled with a bad Arrows team in 1997, finishing outside the top 10 while collecting just seven points. Schumacher departed Benetton following his second straight title in 1995, joining a beleaguered Ferrari squad. Schumacher battled opponents as well as his car throughout 1996, finishing third in the standings while collecting three race wins.

Alain Prost and Nelson Piquet both made the move in the late 1980s; Prost finished second in his first season with Ferrari in 1990, while Piquet checked in sixth in 1988 with Lotus after leaving Williams. If Button wants to win the title this season, he's clearly got some history to battle with.

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AP Photo/Lefteris PitarakisTyhe past two world champions are on one team, with 2008 champ Lewis Hamilton, left, welcoming 2009 victor Jenson Button on board.

Schumacher's return to F1, while not shocking after his attempted comeback last season, certainly raised eyebrows throughout the F1 community.

Following several weeks of preseason testing, Ferrari, Red Bull and McLaren appeared to lead the way, with Schumacher's Mercedes squad (formerly Brawn GP) in the mix as well, if not just a tick slower. Schumacher will have to battle not only a three-year absence from the sport, but numerous rule changes and new competitors, as well.

A revised points system was implemented to accommodate the additions of Hispania, Lotus and Virgin (also with the expectation of USF1's arrival, but that has since fallen through). Mid-race refueling has also been banned, meaning fuel tanks are now much larger and the car has a longer wheelbase and more weight. Also consider the radical design changes the cars underwent prior to the 2009 season, eliminating many of the aerodynamic properties Schumacher previously knew.

Young superstars Lewis Hamilton and Sebastian Vettel have also joined the series since Schumacher retired following the 2006 season.

Even the opening-round venue is not the same as last year.

The 2009 schedule had Australia host the first race of the season, while this year, the venue has been switched to Bahrain. A regular on the schedule since 2004, Bahrain's layout for the F1 race this year has been altered to include the extended backstretch, meaning it is now the second-longest circuit on the schedule behind Spa.

That's great news for Red Bull driver Vettel, who scored two wins and three podiums on the four longest circuits of last season. Keeping with that theme, as Vettel is one of the popular selections to win the championship this season, the winner at Bahrain has won the title in the same season four times out of six.

Felipe Massa is a rare exception; he won the 2008 race at Bahrain, but finished second by a single point to Hamilton in the championship. Keeping with the common theme, Massa too made headlines this offseason with his comeback from injury along with the fact he has a new teammate in two-time champion Alonso at Ferrari.

This season looks to be incredibly balanced at the top, and it's anybody's guess as to who takes home the first race, much less the title.