The sample size argument that you bring to the table is a reasonable one, however I believe that Iwamura has exhibited several traits in his brief stint with the Rays that make my naming him the best player on the team a reasonable assertion at the moment. The hitting ability I discount, because that is prone to streaky play. However his plate discipline, pitch recognition, and ability to extend the counts and make pitchers work to get him out I believe will make him a tough at bat any time he comes to the plate. Those are traits that don't ebb and flow like hitting success. His defense is another aspect I like. I think that his defense, while a trait more prone to slumps than those listed above, is never going to be a tool that will fluctuate. The quick reflexes he shows are a mix of natural ability and experience. The latter will never get worse, and I don't see the former doing so any time soon. I think he is even a better defensive player than Crawford at a more important position, and with a pitching staff that needs all the help they can get, that is extremely valuable. You could argue that Young is better defensively, and I would agree with you, however he is lacking in other areas, namely hitting, that diminish his status where such a comparison is not important in evaluating who is the better overall player.

To be fair, the comment was made in jest and I really didn't think it through to much. I would agree that Crawford is the team's best player, however really it is a toss-up between Iwamura and  Shields at No. 2 for me, with Shields probably getting the edge because he has been comparably dominant for a full season. Delmon Young at the moment is not a good hitter at all, he has no plate discipline and won't even be close to Iwamura until he either develops some or compensates for it with exceptional ability in other areas offensively. His defense, as mentioned before, is superior. His arm certainly is. But the overall package isn't there yet.

B.J. Upton isn't in it for me, not even close. His defensive ability is far inferior, and Iwamura is a better hitter right now despite Upton's torrid start. Though Upton has shown improvement with his K rates as of late, they still are a major black mark overall on his ability to sustain offensive production. I take Iwamura over him in both areas.

Kazmir is tough to gauge. I think Kazmir is, on rate performance, the best player on the team hands down. However he doesn't sustain it long enough to be better than Iwamura at this point. He has been unable on many occasions to proceed deep into ballgames, and he has a penchant for control issues. Despite that last factor, he is still better on rate performance than Iwamura, but his inconsistency in sustaining those impressive rates when he pitches knocks him below Iwamura for me.

For the record, of the six players that you listed, I would rank them as follows:

Crawford
Shields
Iwamura
Kazmir
Upton
Young

Your first remark humbles me. I appreciate the kind words and I'm glad that you like my commentary.