Like Moore and McHugh, he may have found his level scoring against lower league opposition.
Like Thomas, Moore and McHugh were top performers for the U20s, but failed to impress in the first team. The real test for Thomas will be when he is playing against better teams.
Regardless, he didn't want to play for us, so no point in keeping him. And if he thrives at Killie we have a tasty sell-on fee coming our way.