I see, so you want to be certaint that he's good and you can play him. Thanks.
Are rule-5 draft players drafted in the same way as the hs/college kids where worst team has first pick, or is it different?
No, you're thinking of the Rule 4 Draft.
"The First-Year Player Draft, also known as the Rule 4 Draft, is Major League Baseball's primary mechanism for assigning amateur baseball players, from high schools, colleges, and other amateur baseball clubs, to its teams."
"The Rule 5 draft is a Major League Baseball player draft that occurs each year in December, at the annual Winter Meeting of general managers. The Rule 5 draft aims to prevent teams from stockpiling too many young players on their minor league affiliate teams when other teams would be willing to have them play in the majors. The Rule 5 draft is named for its place in Major League Rules. (It is sometimes mistakenly referenced with a Roman numeral.) The June Rule 4 draft, known as simply "the draft", "amateur draft", or "first year player draft", is a distinctly different process in which teams select high school and college players."