What is the average weight in pounds of all the players with the highest prospects for the draft?
average = AVG(weight_in_lbs); weight in pounds refers to weight_in_lbs; players refers to PlayerName; highest prospects for the draft refers to MAX(CSS_rank);
SELECT CAST(SUM(T2.weight_in_lbs) AS REAL) / COUNT(T1.ELITEID) FROM PlayerInfo AS T1 INNER JOIN weight_info AS T2 ON T1.weight = T2.weight_id WHERE T1.CSS_rank = ( SELECT MAX(CSS_rank) FROM PlayerInfo )