HALLANDALE BEACH, Fla. &ndash; Mobilizer, whose only poor performance in five career starts came on the biggest day of his career in the prestigious Queen&rsquo;s Plate, tries grass for the first time when he returns from an eight-month layoff in Thursday&rsquo;s $55,000 allowance feature at Gulfstream Park.\r\nMobilizer was the 7-2 favorite but showed only brief speed before fading badly to finish a well-beaten 10th in the $1 million Queen&rsquo;s Plate. A homebred son of Motivator owned by Frank Stronach&rsquo;s Adena Springs, Mobilizer came out of the race with an injury serious enough to cost him the remainder of his 3-year-old campaign.\r\n&ldquo;He did some muscle damage over his quarters over his back during the race and we had to put him away for quite a while,&rdquo; said trainer Roger Attfield.\r\nMobilizer, who had finished second, beaten just a half-length, by eventual Queen&rsquo;s Plate winner Big Red Mike in the Plate Trial, made all five previous starts over synthetic tracks, the last four at Woodbine. But Attfield is confident he will like the turf even better.\r\n&ldquo;I always thought he&rsquo;d be a better turf horse and his pedigree suggests that as well,&rdquo; said Attfield. &ldquo;He&rsquo;s been training extremely well up here at Payson on the grass.&rdquo;\r\nAttfield will also remove the blinkers he put on Mobilizer for the Queen&rsquo;s Plate when he opens his 2011 campaign on Thursday.\r\n&ldquo;He&rsquo;d run a couple of races where it looked like he would win and hung a little including the Trial, and he seemed to be a bit more aggressive, upside a horse when we worked him in blinkers before the Queens Plate,&rdquo; explained Attfield. &ldquo;But he&rsquo;s been working so much better this year without them I see no reason to start off with them, especially since we&rsquo;re really not sure in the first place whether they&rsquo;ll actually help or not. I think he&rsquo;s matured into a stronger, better horse than last year but you&rsquo;re never really sure until the gate opens.&rdquo;\r\nMobilizer will face a full field of 12 in his return, topped by Devon Rock, Hariolus and Senor Dehere.\r\nDevon Rock was taken up in early stretch, then finished full of run only to fall a nose shy of winning a similarly conditioned allowance race going a mile here four weeks ago. The effort was the best since last summer for Devon Rock who was stakes placed at 3.\r\nHariolus returned from a one-year hiatus to win a $25,000 open claiming race going a mile on the grass here Feb. 3 for owner Frank Calabrese, who twice claimed the veteran grass specialist during his 2009 campaign.\r\nSenor Dehere has yet to run back to his impressive career debut last summer at Saratoga, when he rallied to a 2 1/4-length maiden special weight victory going 5 1/2 furlongs for trainer Graham Motion. Senor Dehere failed as the favorite both over the Polytrack at Keeneland and on the Churchill Downs turf course in two subsequent starts to close out 2010 and will be at a disadvantage breaking from post 12 in his 2011 debut.