PUEBLO, Colo. - Anything can happen in bull riding.

Eighteen events into the 2012 Built Ford Tough Series, it seems that nearly everything has.

This weekend, the Top 35 riders head to Pueblo, Colo., for one last event before the annual summer break.

For the past month, Valdiron de Oliveira has been the No. 1 rider in the world.

Valdiron de Oliveira is trying to maintain his lead going into the summer break.

Despite fracturing his left eye socket in Connecticut, he missed only one BFTS event in Billings, Mont.,  and escaped another serious injury last week in Nampa, Idaho, where he extended his lead in the world standings over Silvano Alves to 654 points.

Alves is attempting to become the first back-to-back World Champion in PBR history, and has employed a conservative approach, declining four re-ride opportunities so far.

Last year, he didn't claim the top spot in the standings until after the summer break, and is in position to do so again in 2012. He and J.B. Mauney are the only two riders with two event wins, and his 38 qualified rides are the most among the top contenders.

L.J. Jenkins is also making a sustained run at the title.

L.J. Jenkins could potentially ride into the lead this weekend.

He's recorded seven consecutive Top 10 finishes - his most prolific two-month period since making his BFTS debut in 2005 -including one event win and six other Top 5 finishes.

He's ranked third, only 740.75 points behind Oliveira.

Jenkins finished last year ranked eighth. His best finish came in 2006 when he wound up seventh.

Guilherme Marchi, who claimed the 2008 title after three consecutive years of finishing second, has quietly ridden his way into fourth place in the world standings.

The veteran has one event win, and his six Top 5 finishes tie him with Oliveira for the third most behind Jenkins (7) and Marcho Eguche (8).

Mauney is out of competition this week because of issues with his hip and left arm. The 25-year-old is in search of his first world title, and for the past three weeks he has been riding with his right hand in the bull rope while recovering from surgery on a broken bone in his left hand.

No rider until Mauney has consistently had success switching riding hands at the BFTS level.

He's ridden three bulls, including two in the 15/15 Bucking Battle, and while he's slipped from the top spot in the standings to fifth in the world, his three scores have kept him from falling far.

Mauney is the only other rider to have been ranked No. 1 for multiple weeks. Cody Nance, who has fallen to 23rd and is virtually a non-contender, was the top-ranked rider after winning the first BFTS event of the season in New York.

There are 1,500 points available in Pueblo this weekend.

The 15/15 Bucking Battle, which takes place Saturday night following Round 2 of the event, is worth a maximum of 300 points, while the Pueblo Invitational is worth 1,200 points.

Any one of the Top 4 riders could take the lead.

And with the number of points available at the three-day event, the entire order of the Top 25 could change going into the break.

Upon the return of the BFTS in Tulsa, Okla., there will be nine more events on the road to the World Finals in Las Vegas.

NEWS & NOTES

TV GUIDE: Friday's opening round can be viewed at the PBR Live Center beginning at 10 p.m. ET. Round 2 can be seen Saturday night on CBS Sports Network at 10 p.m. ET. On Sunday, the 15/15 Bucking Battle will be aired on CBS at 2 p.m. ET., and followed by the final two rounds, which will air on CBS Sports Network at 6 p.m. ET.

DEBUT: "Dangerous Game: Inside PBR," an hour-long roundtable discussion, will premiere on CBS Sports Network on Sunday, May 20, at 3 p.m. ET. The discussion features nine-time World Champion Ty Murray, Luke Snyder, Shorty Gorham and two-time Stock Contractor of the Year Jeff Robinson. Craig Hummer moderates topics such as the growth of the sport, its danger factor, safety issues and the popularity of bucking bulls.