Preliminary estimates for UFC 159, headlined by Jon Jones' successful light heavyweight title defense against Chael Sonnen, indicate pay-per-view buys coming in between 520,000 and 550,000.

If those numbers hold up, it would be in line with most expectations going into the fight. Sources in UFC had, well before the fight, indicated the company's budgetary prediction for the show was 500,000.

UFC 159 took place on April 27 at the Prudential Center in Newark. N.J. Jones vs Sonnen headlined the show, which included Michael Bisping vs. Alan Belcher as the No. 2 fight.

There was hope for bigger numbers in the days after the fight, due to the strong ratings of UFC 159 shoulder programming. The weigh-ins were the second-highest rated since Fuel began airing. The event also drew the highest ratings for post-fight coverage of a pay-per-view on Fuel. Prelim match ratings on FX were 32 percent above average.

The number would be the company's second largest of 2013, trailing UFC 158, with Georges St-Pierre vs. Nick Diaz, but ahead of the now No. 3 event of the year, UFC 157, headlined by Ronda Rousey vs. Liz Carmouche.

The number would be considerably above the 410,000 estimates for Jones' previous title defense, against Vitor Belfort. Most of his main events have fallen in the 450,000 to 480,000 range, except for big numbers for his title defenses against Rashad Evans and Quinton "Rampage" Jackson.

When the fight was first announced, it came under heavy criticism for the most obvious of reasons. Sonnen, who competed as a light heavyweight earlier in his career, was moving up from middleweight after two losses to champion Anderson Silva. He was given a title shot ahead of candidates proven in the division including Dan Henderson, Lyoto Machida and Alexander Gustafsson.

Sonnen was being rewarded, even coming off a loss to Silva, because of his strengths at selling a fight, and because the Jones vs. Sonnen dynamic as coaches was expected to revitalize The Ultimate Fighter reality show.

TUF was coming off its lowest-rated season in history. Ratings were up significantly with Jones and Sonnen as coaches, from season 16's 865,500 average to season 17's 1.2 million. However, a good percentage of that increase also had to do with moving the show off Friday nights, a bad night for the target demographic, to Tuesday.

But the season, praised for having strong fights, failed to have the fireworks between the coaches that in the past has led to blockbuster pay-per-view events like Ken Shamrock vs. Tito Ortiz, Rashad Evans vs. Quinton Jackson and Georges St-Pierre vs. Josh Koscheck.

The number may also have been hurt because few saw Sonnen as a real threat to beat Jones, moving up 20 pounds against the sport's most dominant fighter of the past two years. Jones was as much as a 9-to-1 favorite, the longest odds in any UFC championship match in several years.

The UFC does not release pay-per-view numbers. Final numbers can often vary from the earliest estimates, which are usually based off early reporting satellite systems.