Siente El Trueno will break from post 7 in the featured eighth race Thursday at Fair Grounds, a cautionary tale named Walking the Beach standing in the gate just to his left. Walking the Beach came into the 2009-2010 Fair Grounds meet regarded as a potential Louisiana Derby player after winning his career debut in impressive fashion at Churchill Downs. Walking the Beach has never run back to that first race, losing all seven of his subsequent starts while never finishing better than third. That’s hardly a heartening tale for Siente El Trueno, who might have been the most impressive maiden winner last season at Fair Grounds, capturing his career debut Jan. 23 by more than six lengths with a fast six furlongs. Siente El Trueno did not race again until Dec. 5, and when he returned he looked nothing like the horse of 10 months before. Bet down to odds of 1-2, Siente El Trueno was outrun for the early lead and faded to finish fifth of six in a first-level allowance race. The 4-year-old colt does have a potential excuse for the dud, since he was tried on turf that afternoon. Siente El Trueno is bred top and bottom for grass but might merely have disliked the surface. A return to dirt Thursday could lead to a return to form. Siente El Trueno’s most recent workout, a snappy five furlongs on Dec. 31, suggests that bettors not give up on the horse quite yet. Siente El Trueno is well drawn on the far outside of a short field, with inside speed likely to come from Canon Man, still another horse in the market for a renaissance. Beating Louisiana-breds, Canon Man won the first two starts of his career late in the 2009-2010 Fair Grounds meet, running a fast time in the second victory, but he has since lost five straight. Rail-drawn Z Winner is in the same spot Thursday that Siente El Trueno was last month, making his first start back from a long layoff following a Fair Grounds debut win last season. Z Winner won his race by only a head, earning a Beyer Speed Figure 30 points lower than Siente El Trueno’s, but he has posted a solid work pattern for trainer Steve Asmussen’s Fair Grounds barn and may be ready for a representative effort in his first post-layoff appearance.