It is far more difficult nowadays for a regional stallion to make the leap to Kentucky than in the long-ago days of, say, Mr. Prospector. Sheer numbers work strongly against such a shift.

Grade 1 winner Sharp Azteca, whose retirement was announced in early September, will begin his stud career at Three Chimneys Farm in Kentucky.

Sharp Azteca last raced in January, finishing eighth in the Pegasus World Cup at Gulfstream Park. He was pointing to the Godolphin Mile in March in Dubai – a race he was third in during 2017 – but injured a suspensory ligament in his left foreleg during his final work toward that target. The horse spent some time rehabbing at co-owner Gelfenstein Farm in Ocala, Fla.

Medaglia d'Oro, in the midst of a career run on the racetrack and in the commercial arena, will stand for $200,000 to lead Darley's American roster in 2019.

Medaglia d'Oro, by El Prado, sired seven Grade 1 winners in North America last year - including Breeders' Cup winners Bar of Gold and Talismanic - putting him in an elite club with Danzig, Mr. Prospector, and Storm Cat as the only American stallions to have as many in a single year.

Galileo and now Dubawi have so thoroughly dominated European sire ranks over the last decade that some truly outstanding sires are largely overlooked by pundits and, to an extent, breeders and yearling buyers.

Horse of the Year Gun Runner will stand for an unchanged fee of $70,000 in his second season at stud to lead the Three Chimneys Farm roster, the farm has announced.

Gun Runner, by Candy Ride, entered stud this year after winning the Pegasus World Cup, his sixth career Grade 1 tally, in late January, the day after being named Horse of the Year.

Gainesway stallion Empire Maker, a major influence on the classics in recent years, will stand for an advertised stud fee of $85,000 in 2019, when his return North American crop comes to the races. Empire Maker stood for the same fee in 2018.

Gainesway announced its full nine-horse roster and fees late Thursday night after earlier in the week revealing that three-time leading sire Tapit will stand for $225,000 in 2019, meaning he is no longer North America's most expensive stallion. He stood for $300,000 from 2015 to 2018.

Two-time Horse of the Year and multiple classic sire Curlin's stud fee will climb to $175,000 for 2019, Hill 'n' Dale Farm has announced.

Curlin, by Smart Strike, stood for $150,000 in 2018. The stallion has sired a classic winner or classic-placed runner from each of his first six crops to race, represented by 2013 Belmont Stakes winner Palace Malice, 2014 Preakness Stakes runner-up Ride On Curlin, 2015 Belmont runner-up Keen Ice, 2016 Preakness winner and Kentucky Derby runner-up Exaggerator, 2017 Belmont runner-up Irish War Cry, and 2018 Derby runner-up Good Magic.

Classic sire Pioneerof the Nile will stand for $110,000 in 2019 to lead a strong branch of his sireline on WinStar Farm's expanding roster.

Pioneerof the Nile, by Empire Maker, is the sire of 2015 Triple Crown winner American Pharoah, fellow Eclipse Award champion juvenile and 2017 Preakness Stakes runner-up Classic Empire, and 2014 Preakness third-place finisher Social Inclusion.

International sire War Front's stud fee will remain at $250,000 at Claiborne Farm for 2019, which will keep him among the most expensive stallions in North America.

War Front is the sire of Grade 1/Group 1 winners Fog of War, Homesman, Lancaster Bomber, and U S Navy Flag in 2018. He led the Keeneland September yearling sale by average price, checking in at $782,500, with five seven-figure yearlings sold.

Perennial leading sire Tapit will stand for an advertised fee of $225,000, a reduction from his continent-leading price of the last several seasons, Gainesway Farm announced Wednesday. His book will again be limited to 125 mares.