The Olympics will be safe for all athletes because they are taking extreme precautions entering this years Olympics. Terrorist attacks are an eminent threat so extra security will be everywhere to prevent these attacks. Also Rio doesn't want to gain a bad reputation so they will do everything they can to make it a safe environment for the athletes.
Yes, the Rio Olympics will be safe for athletes. There are concerns about safety surrounding every Olympics due to the fact that it is a world event. This does not mean that the Olympics typically has a safety problem. Some negative occurrences have occurred at the Olympics in the past, however, security personnel have learned from this.
Not only is Rio a dangerous city based on the crime rate, these athletes for the first time also have to worry about the Zika virus. The virus is spreading to different parts of the world, and the rate of transmission in areas like Rio are rising. There has already been theft from Olympic athletes, and there is a real danger of physical harm from criminals.
Rio does not seem to be prepared to host the Olympics. Although 100% safety is never guaranteed to anyone, anywhere, the athletes will be in more danger than necessary during their time in Rio. It is likely that at least some of the athletes, their trainers, or other staff will be infected with Zika virus during the games.