offseason problem

It all comes down to how good your future is in baseball and how much you enjoy basketball. If you really enjoy it you should probably play.

I've seen players get much stronger while still playing Basketball. In fact, it's fairly common in College Basketball programs for a player to gain strength during the season. It's also very good conditioning. Only down side is possible injury that could affect your baseball season.

Agree with PGstaff here. If you love basketball, don't give it up...you only have so much time in high school sports, so enjoy every moment.
Most high School basketball programs that I know of are doing some strength training, whether it be plyometrics or what have you. Might want to check with the coach - that may help you answer your question.