I've never seen an INSERT and SELECT query used in this manner before. If you want player_id,player_name,player_url from table1 to go into table2, then do your SELECT for table1 and put the values into hidden fields as part of the form, then when the user clicks the checkbox, you'll have all the data from all the fields, including the info from table1, to INSERT into table2.
By the way, you are using deprecated syntax. You should be using PDO syntax. Your code as is is subject to being hacked.