Evan Grant responds to Mike Hindman's analysis of the 40 man roster situation, and says that while Hindman would have Metcalf as the first guy off the 40 right now, he thinks Luis Mendoza, Dustin Nippert, and Greg Golson should all get put on waivers prior to Metcalf.
His argument is two-fold -- first, if Michael Young gets hurt and misses a significant amount of time, the Rangers would need Metcalf, and second, some team -- probably the Yankees -- would claim Metcalf on waivers, because Metcalf has a career 775 major league OPS and would be an upgrade over Cody Ransom.
I have to disagree with both of those items, though. First, if Young (for the first time in his major league career) has to go on the d.l. and miss a significant amount of time, I think you probably either go with German Duran, or shift Chris Davis over from first base on an interim basis and get an extended look at Max Ramirez. The Duran option would be the preferred one, but I don't think if Young is going to miss a couple of weeks, I don't think it would kill you to make the position switch for a short period of time.
On the second part...yes, Metcalf has a 775 OPS in a limited amount of major league ABs, driven largely by a bunch of homers. I don't think anyone thinks his .475 slugging percentage is sustainable. His minor league OPS from 2006-2008 has been 623, 729, and 670, and as a result, the projection systems generally see him as mid-600 OPS guy this season in the majors.
What it boils down to is a question of whether you believe in the bat, and whether what he's done in the majors is more indicative of his talent level that what he's done in the minors the past several years.