By Mark Lamport-Stokes LOS ANGELES (Reuters) – Boxing guru Teddy Atlas had to think long and hard before he finally decided to come out of retirement as a trainer and help prepare Timothy Bradley for his WBO welterweight title defense against Brandon Rios next month. It had been more than four years since Atlas last worked as a trainer, acting as cornerman for Alexander Povetkin when the Russian won the vacant WBA heavyweight championship title in 2011 before their relationship soured and they parted ways.