Holt doesn't have greatest range -- "It is what is," Hurdle said -- but it's good enough to get by at SS ... If bat stays hot, Holt could swipe playing time from Barmes down stretch.
I'm not opposed to this, of course, but I think we need to temper our expectations. Holt is better than Drew Sutton, but the same principle applies -- if you're hyping some guy you never heard of before last Wednesday because he came up and had one good game, there's a decent chance you're going to end up looking silly. (I know most of you knew who Holt was before last Wednesday. But if you're on Twitter, you probably understand what I'm talking about -- there's an incredible amount of reactionary stuff out there.)
Holt had a great minor-league season, and he played his way into the team's prospect picture. So far in the big leagues, he's had some excellent at-bats, and I get that people who are used to the Pirates' typically hacktastic approach feel immensely relieved to be able to watch a guy who appears to be able to work the count. But he's never been considered an elite prospect, and before tonight's four-hit outburst, ZiPS projected Holt would hit .250/.308/.333 the rest of the year.
Barmes, meanwhile, is projected to hit .244/.289/.372, so actually, arguably, a bit better than Holt. (UPDATE: Vlad points out in the comments that ZiPS in-season projections are only based on major-league stats, not minor-league ones, so ZiPS isn't factoring in Holt's excellent performance in the minors this year. That certainly changes things. Dan Szymborski, who created ZiPS, writes that Holt's actual rest of season projection is .280/.335/.369, which is obviously much better than Barmes, but still might not be enough to overcome the difference in defense.) Also, defense matters, and Barmes has been very good this year. His occasional failings with the glove have gotten a lot of attention because he hasn't hit much, but Barmes' defense is comfortably above average at shortstop, and I can't remember ever seeing anyone who was really gung-ho about Holt's ability to handle the position full-time.
If I were making the decisions, I'd still go ahead and play Holt a bunch at shortstop, for the same reasons I'd go with guys like Jeff Locke and Chris Leroux in the pitching staff -- the Pirates are behind in the Wild Card race and clearly don't have the talent of a team like the Cardinals, so I'd be looking to gamble with young players (however limited their upside might actually be) rather than just soldiering through with veterans who are known to be mediocre. If Holt has a hot hand, then the Pirates can go with that. But I think it's actually a more marginal call than it might appear to be. Barmes is an extremely frustrating player to watch, but he's not Rod Barajas or Erik Bedard. Even in the midst of a poor offensive year, he has value.