The purses paid at Arlington Park this summer will depend upon the number of starters entered in a race, Arlington and the Illinois Thoroughbred Horsemen’s Association announced Monday.The purse for a given race listed in Arlington’s condition book will be paid in full if seven or more intended starters enter the paddock to be saddled for the race. If fewer than seven horses come over from the stables, only 85 percent of the published purse will be paid out, according to the new rule.Small fields decrease handle on a race, and by paying smaller purses in such instances, Arlington intends to offset handle declines and avoid overpaying purses during the season.“This banking program will allow us to maintain a sustainable purse structure at the most competitive time of the year,” Arlington’s general manager,, Tony Petrillo, said in a news release.Arlington, the release said, also will cease the practice of including purse bonuses, such as those paid to Illinois-bred horses competing in open races, in the listed purse for a race. Bonus money will be listed inside parentheses when it appears in race conditions, as had been the case until two seasons ago at Arlington.