Kentucky Derby 2015: Who to watch

Who to watch in Saturday's Kentucky Derby? The latest season of Triple Crown thoroughbred racing gets underway with the 'Greatest Two Minutes in Sports.'

Updated at 11:45 a.m. Eastern time Saturday: It was announced Saturday morning that International Star has been scratched and will not run in the Kentucky Derby. This comes after news that both Stanford and El Kabeir were also pulled from the race, leaving 18 horses in the Derby field.

Thoroughbred racing fans are expecting a full field of 20 horses in this year's 141st running of the Kentucky Derby at Louisville's historic Churchill Downs early Saturday evening.

And based on a points system begun three years ago that helps determine the most qualified horses for the Derby, there are a number of serious contenders in this year's "Run for the Roses."

Seven of the 20 horses in the field have earned at least 100 points in graded stakes races that lead to Louisville, including the Wood Memorial in New York, the Santa Anita Derby in California, and the Florida Derby. Five more thoroughbreds have garnered at least 50 points.

The points leader with 171 coming into the Kentucky Derby is International Star, who has won four of five races since last fall. Star's biggest victory is the Louisiana Derby back on March 28.

International Star's father is Fusaichi Pegasus, who was the winning horse in the 2000 Kentucky Derby. Star will run out of the No. 12 post position on Saturday.

At 170 points is Dortmund, who has won his last four races, including the Santa Anita on April 4. Dortmund is out of Big Brown, who won both the Kentucky Derby and Preakness Stakes in 2008.

Dortmund, trained by three-time Derby winner Bob Baffert, will start from the No. 8 post, which could provide a benefit early in the race.

"He's a horse that gets going. He's quick. He'll be right there in the mix," Baffert told KentuckyDerby.com.

Next up, with 164 points, is Carpe Diem, a three-time winner in his last four starts. This three-year-old took his name literally on April 4 and seized a win in the Blue Grass Stakes at Keeneland Race Course in Lexington, Ky., putting him in the Derby picture.

Starting Saturday's race in the second post position, Carpe Diem is trained by Todd Pletcher and will be ridden by 2011 Derby-winning jockey John Velazquez.

Pletcher is not concerned about his horse beginning so close to the inside rail.

“In a perfect world, I would have liked to have been more toward the middle with Carpe Diem (and Materiality). But he’s a good gate horse and he’ll have to get away from there quickly," the 2010 Kentucky Derby-winning trainer told reporters early Wednesday evening.

American Pharoah is considered by more than a few racing observers as the horse to beat on Saturday. Pharoah, owned by Egyptian Ahmed Zayat and trained by Baffert, has won his last three races, racking up 160 points. The 2002 Kentucky Derby-winning jockey Victor Espinoza will ride American Pharoah, starting from the No. 18 post position.

Baffert discussed Wednesday's post position draw and where American Pharoah ended up.

"We talked about being on the outside. I feel like 20 would have been great for me. Out there at least you have a little bit of an option. He's fast. American Pharoah is fast," the veteran trainer said after the draw.

Another triple-digit point earner is Materiality, who won the Florida Derby on March 28. Materiality is by Afleet Alex, who won both the Preakness and Belmont Stakes in 2005.

Materiality, also trained by Pletcher, will start the Derby out of the third post position.

Firing Line is another horse to watch during the 141st Derby. We're not aware of any connection between the horse and the political and public affairs show of the same name hosted by the noted conservative William F. Buckley that aired from 1966 to 1999. But the thought of the late founder and publisher of "National Review" pulling for this thoroughbred from another world is interesting to consider.

Englishman Simon Callaghan is Firing Line's trainer. A man who should be used to debate in his country's Parliament commented on his horse coming out of the No. 10 post position.

"I’m very happy with the draw. I believe we’re last to load, which is an advantage. And with the No. 10, you’ve got options," Callaghan told reporters Wednesday.

Hall of Famer and three-time Kentucky Derby-winning jockey Gary Stevens will be aboard Firing Line.

Finally, since the Derby occurs in the hometown of former heavyweight boxing champion Muhammad Ali, we should keep an eye out for Itsaknockout, leaving from the No. 13 post position. His father is Lemon Drop Kid, who captured the 1999 Belmont Stakes.

The horses are expected to arrive at the Churchill Downs starting gate for post time at approximately 6:24 p.m. Eastern time Saturday.

You can watch the Kentucky Derby on NBC and NBCSports.com.