I'm really not sure that I want to participate in this discussion. I have in the past discussed LS here on the BB, and it can quickly get nasty. I'm pretty tired of that--which makes me tired of many of the discussions here! Having said that, I am going to present some facts that are seldom mentioned in these discussions. Caveat: I do not hold to "easy believism," I do not believe that one has to pray to be saved. Salvation comes through heart belief based on the work of the Holy Spirit, but prayer is a work, and we are not saved through works.
Having said that, note this definition of disciple (Gr. mathetes) from my BAGD Greek lexicon: "gener. pupil, apprentice (in contrast to the teacher).... disciple, adherent." (p. 485; italics in the original). Notice that the term "disciple" does not refer to an action of the heart, but to the outward appearance. Thus it is usually used in the Gospels and Acts of outward adherents to the new faith. Note especially John 6:66, where many who were called disciples quit on Jesus because they could no longer agree with His teaching. There is a similar usage in the secular world in China, wherein a person becomes an official "disciple" of a teacher of a traditional art such as kung fu through an outward ceremony. (I have a friend who went through this.)
Now here is a fact not mentioned yet on this thread, indeed seldom mentioned in this debate (MacArthur misses it altogether in TGATJ's first edition): the term disciple never, ever occurs after Acts! From Romans on, Paul never uses it, John never uses it, Peter and James never use it, the author of Hebrews never does--no one does! Instead the term "believe" occurs quite often in reference to salvation, often the Greek article with the Greek participle, "one who believes." And very often salvation is discussed in reference to belief (faith) with no reference to the Lordship of Christ. (For example, read 1 John, where the title "Lord" never occurs.)
that is why I tend to see this in two separate areas...
can a sinner become saved apart from being a disciple of Christ? Yes, as per Apostles John/peter/paul, as they all wrote that whosoever believes in him shall be saved, but they also all added that once saved, that person must become His disciple, in order to experience becoming conformed into image of jesus!