What was the significance, if any, of this man? Was he one of the disciples?

This is from Coffman NT Verses 51, 52 And a certain young man followed with him, having a linen cloth cast about him, over his naked body: and they lay hold on him; but he left the linen cloth, and fled naked. These verses, peculiar to Mark, are presumed by many to be a narrative of what happened to Mark himself; and there is general consent that this is the case. It cannot be proved, of course; but the supposition fits all the facts. As to the reason for his inclusion of this incident in a gospel that omits so many weightier matters, it has been alleged that this may be construed as a kind of signature to the Gospel. It is the conviction here, however, that the significance of it lies in the fact that as soon as the arresting group had Jesus in their power they began also to arrest his followers. Certainly, they did lay hold on the young man here; and the parallel fact of their not taking any of the Twelve gives powerful inferential corroboration of the Johannine account of Jesus' forcing an exemption of the apostles from that arrest.