Chicago recently traded Patrick Sharp and good defensive prospect Stephen Johns to Dallas for Trevor Daley, Ryan Garbutt, and (most important here) cap relief.

This was a necessary move for Stan Bowman, obviously, but one that leaves a lot of questions, not the least of which are, “Why does Dallas feel as though it needs another forward?” and “Seriously, shouldn't Jim Nill be trying to get some help on defense?”

It also leads one to wonder what Bowman sees in Daley. He had to take bodies back, of course, and even with Dallas retaining some of Garbutt's salary, the Stars were probably happy to rid themselves of their long-time defenseman. Daley has a reputation as being a very good defenseman, but he's coming off a deeply awful season. And now that he's 31 (and will turn 32 in October), there are legitimate questions as to whether the Daley of last season — who, again, is bad — is the Daley we can also expect going forward. Most players do not get better after their 30th birthday, and there's plenty of data to suggest that's especially true of defensemen in particular.

Scroll to continue with content Ad

Story continues

In reality, though, Daley has obviously always been better than above-average defensemen in this league, so a slide from “good” to what he was last year (below-average in a lot of areas) is a worrisome drop to say the least. Now, that comes with the understanding that Daley actually posted career highs in both goals and points last year (16-22-38), both by fairly large margins, and in only 68 games so perhaps Bowman is banking on him being able to continue putting up those numbers when he gets onto what is clearly a better overall team. If, for instance, you stick him with Niklas Hjalmarsson and he gets a lot of ice time with Patrick Kane, that's likely to produce similar results than even time with Alex Goligoski, Jamie Benn, and Cody Eakin, who were Daley's three most common teammates last season.

It is, though, easy to be enamored of defensemen who post 38 points in 68 games. And not that Bowman hasn't managed his team exceptionally in recent years, but those numbers do make it easy to overlook another thing that helps boost your goal totals: Posting the highest shooting percentage of an 11-year career by almost 70 percent.

However, we're also talking about a guy who's going to spend all but four or five days of the season as a 32-year-old, meaning that he's getting to the age when the wheels for defensemen tend to just fall off. Kevin Bieksa is a guy who gets talked about a lot when it comes to this sort of thing, because he's a defenseman who went from being just a step below Norris-caliber to getting run over in the playoffs by the Calgary Flames in about two and a half seasons. Those seasons were his age-31 through 33 years, and that's no coincidence. It's not hard to see Daley — who never approached Norris quality but was often reliably good and occasionally very good — falling into that same category.

No surprise, either, that age 32 or so is about when you start see defensemen dropping out of the league like crazy. What the chart below means is that from 2007-08 until this past season, 223 defensemen played in this league as 24-year-olds, and so on. Those numbers also include those who made as little as one appearance at a given age.





Those numbers show the trend pretty clearly: defensemen are most likely to be in the league from their early- and mid-20s to their late 20s and very early 30s. After that, they just wash out. These numbers also extend well past 35, of course, but the number at that point gets so small, and the level of play for many of those defensemen still so elite (you're getting into Brian Rafalski, Nicklas Lidstrom, Zdeno Chara territory if guys can keep playing at 35-plus) that they're hardly representative.



Daley, I think, doesn't fall in the group of “guys who are likely to stick around past 35” and so you'd have to say we're nearing the end of the line as far as his usefulness goes. What's also interesting about last season was that it was probably the easiest season he's had in terms of usage for some time (still-tough competition but a lot more offensive zone starts), so the fact that he got run over in a lot of respects should add further worry. And what's interesting about that is such treatment from a coach — that is, protecting a veteran like that — flies in the face of how older players are traditionally used.

Yahoo Sports



As you can see, veterans usually take both harder competition and more own-zone draws, while younger guys are sort of eased into the league as a whole. Daley's competitors are typically harder to play against than the highest numbers on this chart (he came in at 17.7 last season, for instance), but for the first time in a while, he was well north of 52 percent OZS%.



The good news is that if Daley is like most defensemen, his offensive numbers should hold up in the same pretty-good range he's enjoyed for years, because the drop-off once you get past your peak around 24, 25, and 26, things just kind of level off on a slow downward grade until you get closer to 35 years old. Daley probably has a few more years left of putting up decent numbers, then, even if last year's were a percentage-drive fluke.

But the bad news is that there might not be much even the hyper-efficient, mega-effective, star-making system Joel Quenneville runs (augmented by high-test talent) will be able to do to keep Daley's numbers above water. For his age, he's traditionally above-average in comparison with just about every number seen here, but we're getting into a real worrisome spot. After 30 or 31, things tend to hit the skids, and hit them hard.

If Daley follows a similar trend, he's potentially headed for a really bad crash here. There is, again, enough talent in Chicago to potentially keep him afloat better than players getting similar ice time in Dallas, but it wouldn't be that surprising to see him relegated to a guy about whom Chicago fans spend a lot of time complaining. He gets $3.3 million against the cap for each of the next two seasons, and that contract is likely to outlast his utility.

His numbers have been headed in the wrong direction for years at this point, and the only thing he can really hope is that his point production continues to outperform the declines in chances and possession shares, which haven't been good to begin with. If not, this trade is going to be as lopsided as people already think it is.

(All statistics via War on Ice)

Ryan Lambert is a Puck Daddy columnist. His email is here and his Twitter is here.

MORE FROM YAHOO SPORTS: