Last year, we looked at some of the offseason's top free agents from a "half-full, half-empty" perspective. Let's do that again this year and start with Jon Lester, who is expected to meet this week with the both the Chicago Cubs and Boston Red Sox, the early leaders in the rumor mill to sign Lester. With the Cubs, Lester would reunite with Theo Epstein, his former general manager in Boston. With the Red Sox, he would return to the franchise where he played nine-plus seasons before his trade deadline deal to Oakland in 2014.

As Gordon Edes wrote last week, the Red Sox will have to make a big increase over what they offered Lester last spring,

[A] quick deal with the Red Sox cannot be ruled out altogether. The Sox have never made an offer beyond the four-year, $70 million one they made in mid-March last spring, but sources with direct knowledge of the Sox offseason plans say that Boston may be prepared to offer as many as six years for Lester, with one source speculating the bid could reach the $132 million threshold.

That's about what Jim Bowden projected for Lester in his free-agent signing predictions: Six years and $138 million, an annual average value of $23 million.

Is the left-hander, who turns 31 before the start of the the 2015 season, worth that kind of money? Let's take a look.

HALF-FULL

In Edes' story, he mentions a 221-page portfolio that's Lester agents, Seth and Sam Levinson, have prepared. One item in there compares Lester's record through age 30 to other great left-handers of the past. It's true that many of the game’s best lefties had more value in their 30s than in their 20s, including guys such as Carl Hubbell, Warren Spahn, Steve Carlton and Randy Johnson. Recent lefties or current lefties such as Tom Glavine, Jamie Moyer, Andy Pettitte and Mark Buehrle also remained successful well into their late 30s.

That doesn't guarantee anything, but it ties into two important factors when considering Lester. First, he's coming off perhaps the best year of his career, going 16-11 with a 2.46 ERA, numbers that included a career-low walk rate and his best strikeout rate since 2010. Lester changed his style of pitching in 2014, throwing more cutters and essentially dumping his changeup. His percentage of cutters increased from 21 percent in 2012-13 to nearly 30 percent in 2014 and his percentage of changeups declined from 12 to 3.

Unlike many cutters, Lester's works as a true strikeout weapon, as he registered 72 strikeouts on the pitch while limiting hitters to a .234/.290/.367 batting line. The cutter is one reason Lester actually had a reverse platoon split in 2014; right-handers just don't do a lot of damage against it. You can see from the heat map why, as the pitch really rides in on them:

ESPN Stats & Info

The other reason to bet on Lester is this guy is one of the most durable starters in the game. He's made 30-plus starts seven seasons in a row and has topped 200 innings in six of those seven years. Lester had non-Hodgkin lymphoma in his rookie season but he's never had any issues with his arm. He's also been terrific in the postseason in his career, with a 2.57 ERA in 84 innings. He's pitched in big games and won big games, something that general managers and managers like to have on their staff. (Yes, his start against the Royals in the wild-card game wasn't terrific, but Bob Melvin left him a little too long and he got dinged and blooped a bit to some extent.)

With a six-year deal, you're getting Lester from ages 31 to 36. If we estimate the average cost per win above replacement on the free-agent market going at about $7 million, Lester would have to earn about 20 wins above replacement over the life of the contract to be "worth" that $138 million price tag. That's 3.5 WAR per season; since 2008, Lester has averaged 4.3 WAR per season. He seems like about as safe a bet as you can have for $138 million.

HALF-EMPTY

To buy into Lester, you really have to buy into his 2014 season -- a season, by the way, which wasn't quite as good as that glossy 2.46 ERA would suggest considering he allowed 16 unearned runs.

Anyway, Lester was a better pitcher in 2014; but in 2012-2013, he went 24-22 with a 4.28 ERA. There's always the risk you're getting that pitcher instead of the 2014 version. Even including 2014, over the past three seasons among pitchers with at least 500 innings, he ranks 31st in ERA, 29th in WAR, 23rd in strikeout rate and 19th in FIP. He's good, but he's really been more of a No. 2 starter in his career than a No. 1. At that estimated AAV of $23 million, he'd be priced right below Clayton Kershaw ($30.7 million), Justin Verlander ($25.7 million) and Felix Hernandez ($25.0). Is Lester really on that top tier of starters? He's received Cy Young votes just twice in his career.

Plus, just look at the Verlander contract as a reminder of the risks in signing any pitcher to a long-term deal, especially when valued at over $100 million. Or CC Sabathia, another lefty who had been durable and had no arm issues when the Yankees gave him a $122 million extension that covered ages 31-35. (He has a 4.21 ERA in the three years since signing that contract and pitched just 46 innings in 2014.) The point: Pitchers are always risky no matter their health history.

There's also this. Lester's fastball velocity has slowly declined through the years:

2009: 93.5 mph

2010: 93.0 mph

2011: 92.7 mph

2012: 92.5 mph

2013: 92.6 mph

2014: 91.7 mph

Yes, the increased use of the cutter helped in 2014, and a lefty who throws 91-93 still has plus velocity for a major league left-hander. But you have to wonder what the long-term outlook will be if he keeps losing a bit off his fastball.

What do you think? Half-full or half-empty on Jon Lester?