Everyday Player > Reliever
Brad Lincoln is 27, and at this point, there's no indication that he can be a good starting pitcher. He isn't able to throw hard enough in that role, and his repertoire isn't varied enough.
He can be a good reliever, perhaps a great one. But a reliever just isn't as valuable as a good everyday player. Pirates GM Neal Huntington has proven that he can find good relievers on the cheap. Jason Grilli. Octavio Dotel. Joel Hanrahan. Javier Lopez. Losing Brad Lincoln hurts, but if you can find a potential everyday player, you take that chance. The Pirates are in the midst of a pennant race, and they really could've used Lincoln, but they can also really use an outfielder who can hit.
So what about Snider? It's worth pointing out, to start, that the Blue Jays are making this deal because they're giving up on him. He was once regarded as their top prospect, and they wouldn't ship him out for a reliever unless they weren't as high on him as they once were. Huntington has traded for former top prospects before, and it hasn't turned out well. The last thing anyone wants is for the Pirates to send out a shutdown reliever for the next Andy LaRoche or Lastings Milledge. The best question about the trade right now, I think, is why a smart organization like the Jays was willing to give Snider up.
That said, I think there's more than enough evidence to suggest this move is likely to be different from the LaRoche and Milledge moves. For one thing, Snider is hitting really well right now -- he hit .335/.423/.598 in 209 at bats for Class AAA Las Vegas this year, and .250/.300/.556 in a brief trial at the major-league level. Las Vegas is admittedly a great place to hit, but Snider hit well on the road, too. He's a lifetime .308 hitter in the minors.
He hasn't fared so well in the majors, but he's only 24, and other than a 241-at-bat stretch in 2009 as a 21-year-old, the Blue Jays haven't really given him time to settle in. That probably sounds like a red flag, but check out Tom Dakers' explanation as to why that was:
The next couple of years, well, he clearly wasn't a favorite of former Jay manager Cito Gaston. Snider was up and down a lot. Cito likes his hitters to go up looking to pull the ball. Travis has good power to the opposite field and didn't agree with the all-out pull philosophy. Cito had the same complaints about Shawn Green and John Olerud ...
I think if he gets 500 at bats, he'll figure things out. The organization seemed to give up on him, I'm not really sure why.
The statistics sure make it look like Snider sure has it in him to be a middle-of-the-order bat, and middle-of-the-order bats don't grow on trees, especially middle-of-the-order bats who are under team control for four more years.
Snider's hitting, at least on a stat sheet, is a little like that of Pedro Alvarez. He's a lefty power hitter. His hitting in the minor leagues was very good, but it was marred by issues with strikeouts, which have led to issues with his on-base percentage at the major-league level. Snider admittedly isn't known for having the all-world power that Alvarez does, but he's a year younger than Alvarez, and his strikeout problems are less extreme. There's also the fact that Snider will be making the transition from the A.L. East, where he was facing very good pitchers most of the time (although, strangely, Snider has a 1.024 career OPS against the Yankees) to the N.L. Central, and he should get a boost from the worse competition there.
With Snider, the Pirates' offense against righties will be a little bit strange, with Snider, Alvarez and Garrett Jones all likely posting low on-base percentages and hitting lots of home runs. But that's just what Snider will likely be right now. The Pirates control his rights for four more years, and with consistent big-league playing time, he could easily develop into something much better. Travis Snider might well turn out to be Lastings Milledge. That's absolutely possible. But let's not forget that Brian Giles was only a little more established than Snider is now -- and a couple years older -- when the Pirates traded a reliever for him. Let's give Snider a chance.