If you say that someone or something is in the ballpark, you mean that they are able to take part in a particular area of activity, especially because they are considered as good as others taking part. This puts them in the ballpark and makes them a major player
If something such as an amount or claim is in the ballpark, it is approximately right, but not exact. If you compare it to some of the other surveys that have been recently conducted, then it is in the general ballpark
A ballpark figure or ballpark estimate is an approximate figure or estimate. I can't give you anything more than just sort of a ballpark figure Ballpark estimates indicate a price tag of $90 million a month