Winter begins 18 days early at the Big A today when racing moves to the inner dirt track, where it will stay until mid-March. No more turf racing. All sprints are run at six furlongs; no more seven furlongs or a flat mile out of the chute. Races at a mile or over will be run around two turns.

There are a number of handicapping adjustments to make for the IDT.

JOCKEYS: Top guns like Jerry Bailey, Johnny Velazquez, Edgar Prado and Jose Santos are moving their tack to Florida.

Javier Castellano ran away with the meet title last winter and figures to repeat. Rich Migliore figures near the top of the list. Shaun Bridgmohan, Aaron Gryder and Mike Luzzi are IDT stalwarts. Chucky Lopez is especially strong on speed horses.

Jorge “Chop Chop” Chavez is staying home this winter. Norberto Arroyo Jr. was heading south, but he’s been getting good mounts so he’ll also remain.

Look for Pablo Fragoso and Tim Thornton to be the go-to bug boys.

TRAINERS: Gary Contessa, with 200 starters last year, won 29 races, edging out Rick Dutrow Jr. (111 starts, 26 wins). Contessa and Dutrow are based right here at Aqueduct, which gives them a slight edge over barns shipping in from Belmont Park.

Mike Hushion, Pat Reynolds and Jimmy Jerkens had solid meets last winter. Other trainers among last year’s leaders were Bruce Levine, Greg Martin, Jennifer Pedersen, Frank Laboccetta Jr., Bobby Barbara and Dominic Galluscio.

Powerhouse horsemen Todd Pletcher and Scott Lake, neither of whom finished in the top 10 last winter, will have much stronger contingents for this meet. Other outfits that figure to have a higher profile this year are Steve Klesaris, Allen Jerkens, Jason Servis, Ben Perkins Jr., Frank Generazio and Kate Demasi.

HANDICAPPING HINTS: Strangely enough, in some ways the inner dirt track resembles Saratoga more than the main surfaces at Aqueduct or Belmont. The turns are tighter: You don’t want to make any wide, sweeping moves on the far turn here, and outside post positions going two turns are the kiss of death.

As at Saratoga, early speed is a big advantage, especially inside speed. Sprinters drawn toward the rail can stretch out going two turns to win at distances up to a mile-and-a-sixteenth.

Also like Saratoga, the IDT is a horse-for-the-course racetrack. Look for horses that ran well here last winter, especially if they’ve been rested earlier in the year. As the meet progresses, give the edge to horses with good efforts over the track at this meet. Multiple winners over the IDT last year (courtesy of “Aqueduct Inner Track Handicapper”) include Sweet Wheeling, Captain Red, Minor’s Gold, Classic Endeavor, Zacharov and Netcong.