I think there's some confusion as to why we're talking about trading Dan Wheeler. I want to clear some of that up.

No, his name hasn't popped up in trade rumors, we aren't saying that it has. We're simply presenting facts as to why he seems like the smarter choice to trade.

Well then are we saying he's a poor pitcher? No.

Here's what we're saying:

Wheeler's ERA was very shiny. Here's why:

.202 BABIP.
That's with a 17.5% line drive rate. Wheeler's career BABIP is .298, and the three years prior average out to just under that at .288. When this regresses - and yes, it will - it's going to result in more hits, and if Wheeler's homerun issues are still existent - they almost certainly will be - then we're talking about more baserunners for a pitcher who gives up homeruns. You can see the problem there.

78.9 LOB%.
In 2007 his LOB% was way unlucky, 61.5%, naturally it shot up to levels Wheeler's unlikely to maintain. I'm guessing this regresses to the ~75% range, but it could go lower. Again, Wheeler will allow more hits next year, and if his homerun problems flare up...

Wheeler's ERA was also misleading. Here's why:

Declining strikeout rates and velocity.
Wheeler's career K/9 is 8.05, last year it was 7.19. Guys generally don't fall off like that, but Wheeler also saw his velocity drop. Injury, age decline, release point issue? Not sure, still not encouraging news.

Increasing flyball rates.
This plays hand and hand with the homerun problems. For the third consecutive season, Wheeler gave up more flyballs than the year prior. The issues with this are intuitive and don't bare repeating.

Decreased slider usage.
If you've seen Wheeler's slider from the back-angle, it's pretty damn awesome. So why is it that his slider decreased in velocity and usage yet again? In the playoffs, Wheeler seemed reluctant to throw his slider, despite it being his best pitch.

The most concerning...

Wheeler's pLI was 1.72 last year. That's the highest leverage index of his career. Simply put, that means he pitched in the toughest situations of his career. Combined with his highest FIP since the Devil Rays days and you're talking about a bad combination.

Moving forward.
Given all of that, confidence in Wheeler's abilities is shaky. Since 2005 his win values have been: 0.7, 1.7, 0.7, and 0.1 last year. Best case: he's worth ~0.7 wins next year. Worst case: the slide continues downward and we're talking about a replacement level relief pitcher.

Why is Wheeler replaceable?
Because almost all non-ace relievers are. Consider Jason Hammel and Wheeler.

Hammel had 50.2 relief innings, and 78.3 total. His full-season FIP was 5.25 and pLI of 0.80.
Wheeler had 66.1 relief innings. His full-season FIP was 4.49 and pLI of 1.72.

Wheeler produced just more than 0 leveraged runs saved. Hammel just under -5.2 leveraged runs saved. The difference between the two - despite the roles - was a half of a win.

In park-adjusted win values, Wheeler had 0.1, Hammel -0.1. That's over/under replacement level. Remember, Wheeler is being paid millions, Hammel hundred-thousands. Hammel is also a DFA candidate.

But he just signed an extension...

Well yeah, and given what we knew at the time, the extension was hardly foolhardy. If the team feels Wheeler is more likely to continue his decline, they have two choices:

A) Sit on the contract.

B) Acknowledge that information gained following the extension and use it in making a sound decision.

Which implies the organization is open to changing their minds, and that's an extremely important attribute.

Stat glossary.