Why are vet starters Lynn, Cobb unsigned?

Lance Lynn and Alex Cobb are a pair of 30-year-old mid-rotation starters with a lot in common. They're both first-time free agents coming off their first full seasons back from Tommy John surgery. They each received and declined a qualifying offer last fall.
Most importantly, of course, as camps open across Florida and Arizona this week, they're both still looking for a team. Why?
It's both simple and complicated. Almost any team, with few exceptions, would benefit from adding a competent veteran starter like this for depth. But then you dig in a little deeper and you see all of the forces that are conspiring to limit the markets for these two. There might only be a handful of teams that are actually bidding, and that could incentivize those who are to wait until they get the deal they're looking for.
Part of that can be attributed to the larger free agent freeze that's affected dozens of players, including Eric Hosmer and J.D. Martinez, but it basically comes down to these three reasons:
• The qualifying offer is a bigger impediment than you might think
• Not every team is actually looking to add a starter
• Teams don't view Lynn and Cobb as elite starters
Put all that together and we might be down to only a half-dozen teams.

Let's clarify what we mean about their that last part, first. Both Cobb and Lynn have had their share of success in the past. In 2013-14, Cobb tossed 309 2/3 innings with a 2.82 ERA. Lynn was an All-Star in '12 and threw 203 2/3 innings of 2.74 ERA ball in '14. After returning from surgery, each had seasons last year that were superficially good (Cobb: 179 1/3 innings of 3.66 ERA; Lynn: 186 1/3 innings of 3.43 ERA) that were not really supported by the underlying numbers or '18 projections.
That's largely because neither one missed bats, nor have they ever, really. Of 125 starters to throw 100 innings, Lynn's 19.7 percent strikeout rate was 77th, behind James Shields and Ian Kennedy. Cobb's 17.3 percent rate was 98th, behind Clayton Richard and Kyle Gibson. Lynn's control issues remained (his 10.1 percent walk rate was the 13th highest of those 125 starters), and Cobb all but abandoned the split-change that had made him effective before he was injured.
These concerns are largely why every major projection system has limited optimism for 2018. In a world where 2 WAR is considered average, Steamer and ZiPS have each of them between 1.5 WAR and 2.8 WAR, or roughly average. PECOTA is even less optimistic, especially on Cobb, seeing below-average strikeout stuff mixed with below-average ability to limit hard contact. He's also never pitched 180 innings, though he missed that mark in 2017 by only two outs.
Now, you don't have to buy into any of those numbers, and that's fine. Both players were better than that just last year. It's just important to realize that every team operates on a version of the same projections.
Still, these are arms with some track record and postseason experience. Why aren't more clubs interested? Here's why.

Teams that don't need another starter
Most teams could use more depth, but not all of them.
Though Cobb was long tied to Chicago, the Cubs addedYu Darvish and Tyler Chatwood to Jon Lester, José Quintana and Kyle Hendricks, filling up their rotation. You can say the same thing for the Gerrit Cole-infused Astros, so deep that Brad Peacock may not have a spot, or the Indians, who may need to decide which of Mike Clevinger or Danny Salazar is the odd man out.
We'll include Arizona here as well; you could argue for Lynn or Cobb over Taijuan Walker, Zack Godley or Patrick Corbin behind co-aces Zack Greinke and Robbie Ray, but if they're an upgrade at all, it's not enough of one to make it worth it. Colorado fits here too, as the Rockies seem to be perfectly happy with their young rotation. We'll reluctantly add the Angels as well, because they are already planning a six-man rotation with what they have, despite health questions about nearly everyone.
Teams over the luxury tax who would be especially penalized for signing a qualifying offer player
Five teams went over the luxury tax limit last year: The Dodgers, Tigers, Nationals, Giants and Yankees. The rebuilding Tigers aren't in the market, so we'll set them aside.
For the rest, it's important to remember what the newest rules for signing a qualifying offer player are. Unlike the previous system, which required a team surrender its first-round pick (unless it was choosing in the Top 10) for signing a free agent who had declined a qualifying offer, now it's a more complicated system based on whether a team participates in revenue sharing and what kind of contract the player signs.
What this means for these four contenders -- exactly the type of teams a free agent would want pushing their market along -- is that the penalties are harsher than for other clubs. If they sign Cobb, Lynn, Greg Holland or any other player who declined a qualifying offer, they'll have to give up a second-round pick, a fifth-round pick, and $1 million from their 2018 international pool.
That last part is a big deal. To sign Cobb or Lynn, these teams would need to surrender two picks, maybe lose 10-to-25 percent of their entire spending room (depending on their allotment), and possibly make it more difficult to stay under the cap this year. That's a lot to swallow for a mid-rotation starter who isn't likely to significantly change playoff odds.
Let's include the Red Sox here, too. While they didn't pay the tax last year, they are already expected to be over for 2018, and might only continue to go past that for Martinez, not another starter.

Rebuilding teams who aren't ready to invest in a mid-rotation starter
Obviously, Cobb and Lynn would each be a boost to the White Sox, Marlins, Padres, Tigers, Reds, Braves, Pirates, Orioles and Royals. They might even be Opening Day starters there, and in some cases, like in Baltimore, they don't have enough pitchers to even fill out a rotation. They'll make adds, but it probably won't be for pitchers who don't have the qualifying offer attached. (Teams who didn't go over the luxury cap would lose their second-highest pick and $500,000 of pool space.)
The two teams who don't need to worry about the qualifying offer
Returning to the Cardinals and Rays for Lynn and Cobb, respectively, would get them around the issue of qualifying offer compensation. But even that's an issue, because their former teams would lose the pick they're expecting, which could be as high as after the first round in some cases. This seems unlikely.
The teams who should be interested, but don't seem to be
We'll put five teams here: the Mets, Rangers, Mariners, A's and Phillies, though in two categories. The Mets have seven starters who made 10 starts last year, plus Noah Syndergaard, and they insist they're pleased with that depth, though a good argument can be made for more. It's similar in Texas, where the Rangers have added Doug Fister, Matt Moore and Mike Minor, plus are giving Matt Bush a chance to start, and they don't seem motivated to do more. The Mariners are also banking on health, with little in the way of depth.
The A's and Phillies are coming at it from a different angle. They're both very interesting and young teams, with low payrolls and youthful rotations, who could use some veteran certainty in the rotation. One thing to note about the Mets, Rangers and Phillies is that they don't receive revenue sharing and didn't exceed the luxury tax last year, so they would have to forfeit their second-highest Draft pick and $500K in international money to sign a guy who got a qualifying offer, which could be a factor here. (The A's and Mariners received revenue sharing, so would only have to give up their third-highest pick.)
The best bets
We're left, then, with three teams: The Brewers, Twins and Blue Jays. All plan to contend in 2018, and all need a starter, in part due to injuries to Jimmy Nelson (Milwaukee) and Ervin Santana (Minnesota). The Brewers and Twins were publicly in the mix for Darvish before he went to the Cubs, and the Jays have been open that they'll add a starter -- and then did sign left-hander Jaime García on Thursday.
Between Arrieta, Lynn and Cobb, there's three solid starters left. All three are past their 30th birthdays, have the qualifying offer drag, and bring some questions about their recent performance. With perhaps only three obvious places in the mix, you understand why this is taking so long. Each suitor can stand to wait for the deal they want to come to them.