The speed of the Del Mar main track has quickened, with a corresponding increase in the number of come-from-behind winners. This is not a coincidence.

For much of summer, Del Mar’s main track was slow and deep. Closers struggled; most races were won by front-runners and pace-pressers. The dynamic has changed.

The surface is faster, not by much, but noticeable. In most races, the pace is realistic, and late-runners struggle less. They settle, and they finish. They did in both dirt routes on Wednesday. If the surface speed stays the same Thursday, one can expect positional movement from the back of the field. Preview …

Race 1 – Altaira (3) wheels back eight days after a wide-trip runner-up finish. She has speed, and can rally. Generous price at 7-2 in this $12.5k claiming sprint.

Race 2 – Both mile dirt races Wednesday were won by closers. If the track plays similarly Thursday, closer Shackleford Banks (6) can win this $20k claiming mile by rallying from behind at 4-1.

Race 3 – Relentless Miss (6) most probable winner on the card? Based on her third-place finish two starts back at Aqueduct, and likely improvement first in California for Richard Baltas, you’d have to say yes – Relentless Miss is the most probable winner on the card facing a modest maiden-62.5k field at a mile on turf.

Race 6 – Same as race 3, Baltas and jockey Rafael Bejarano with a turf-route favorite. Sea Smoke (4) rallied from off the pace to finish second last time in a race won by the pacesetter. Most turf races this summer have been won by closers. This Calbred N1X might be another.

First post Thursday is 2 p.m.