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.[1] 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."