With the trade deadline looming, much speculation has gone on regarding potential moves for the Pirates. One oft mentioned name is the seemingly beloved Hunter Pence. I will be comparing Pence to Jose Tabata, as it has been brought up that it may take Tabata to bring Pence to Pittsburgh. I would also mention Garrett Jones and Alex Presley in the other corner outfield slot, but since Presley's play of late has muddled that situation, and the sample size is far too small to evaluate him, I will stick with Tabata. One thing to bear in mind is that Pence is under control through 2013, while Tabata is under control through 2016. Another factor is Tabata's age, which at 22 makes him a more likely candidate for future improvement. Another (seemingly obvious) factor is how much Pence will cost, which appears to be substantial to say the least. But enough of that, let's get to the fun and look at the numbers.
First up, Pence. Pence is in the midst of a fantastic season for the Astros. At the all star break he has provided 2.7 WAR, putting him on pace for roughly 5 WAR this season, provided he sustains his current .323/.364/.496 line. He has also been a solid player throughout his career providing from 3.3 to 4.1 WAR in each of his four seasons.
At a glance, this season would seem to simply show improvement from Pence, but further examination does not agree. If you look at his numbers, he has a of .389, which is quite high. Obviously, that should regress. But how far? Pence has a lifetime BABIP of .328, but that includes two outlier seasons of .377, and .389 (this season). In his other seasons, his BABIP has been .301, .304, and .308. Since Pence does not hit line drives at a high rate, and does not have plus speed, his BABIP should be somewhere in the neighborhood of the baseline .300.
With his strikeout rate a not very good 20.8%, if you normalize Pence's line for say a, .310 BABIP, he is projected to have about 92.53 hits, we'll round him to 93. That's a far cry from the 117 hit he has so far this season. That would drop his average all the way to .263, which would be the worst of his career. And since Pence's good line has been mainly due to his average, that would give him a terrible season. Let's look at why.
Pence has a poor BB% at 6.1, but that isn't out of line for him (career 6.7). His K% is up this season, to a career high 20.8% (career 18.2). His isolated power is at a career low .173 (career .191). This is despite a LD% that is actually well above career norms at 17.8% (15.7 career). His low line drive percentage actually mean his BABIP should be below the .300 norm, let alone the generous .310 that I gave him above.
Pence simply isn't making contact very well this season. He has not improved, he has actually performed worse than usual, and just gotten extremely lucky. That certainly doesn't seem like someone worth a boatload of prospects, especially since Fangraphs fielding usually gives him very high ratings, but he is at -2.5 so far this season.
Now, as for our comparison of Tabata. Tabata is difficult to project due to a limited sample size, but he has provided approximately 3 WAR over his first 162 games as a professional, and 1.2 thus far this season.
Some people have been disappointed with Tabata's year thus far, with a .265/.351/.354 line. His BABIP so far is .305, as opposed to .339 last season. And this is where using .300 as a baseline can get you into trouble. As Luis Castillo showed for years, your BABIP can be influenced if you have plus speed, which Tabata does. The general rule of thumb I came across is to add .02 of BABIP for each percentage point a plus runner's GB% is abouve 45%. And Tabata is hitting ground balls 61% of the time this season. That would give him a BABIP of around .332, much closer to his .339 of last season. This demonstrates that Tabata seems to be getting unlucky this year.
If we normalize Tabata's line with a .332 BABIP, we find out he should have about 72.72 hits this season, or 73, which is an improvement over the 68 he does have.This would give him an average of .284, which with his greatly improved walk rate would make him a fantastic leadoff hitter.
Tabata's walks are way up (11.1% as compared to 6.3%), his strikeouts are also slightly up (14.8% as compared to 12.9%), his isolated power is down (.089 as compared to .101), and his LD% is slightly down (15% as compared to 16.1%).
Tabata has performed slightly worse this season, but his greatly improved walk rate should make up for the slight regression. He also has a positive fielding rating at 0.6 (1.6 last season).
The final normalized lines (provided BB% and ISO stay the same) come to:
Pence: .263/.304/.436, for an OPS of .740 with poor defense this season.
Tabata: .284/.370/.373, for an OPS of .743 with slightly above average defense this season.
The point of all this is to show that Pence has been getting lucky this season. He has not greatly improved, he is not worth a bunch of prospects, he is only marginally better than Tabata, if at all, and certainly isn't worth Tabata. And he also comes with fewer years of control, and less hope of improvement. Is Pence likely better than what the Pirates will get in right field? Yes. But he isn't worth trading for right now. You never want to trade for a player at their peak value, especially when that peak is an artificially induced one.
(All stats courtesy of Fangraphs and this was a wonderful article about normalizing BABIP for players.)