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By the time TwinsFest jolts baseball fans in mid-January, we usually know what the Twins' roster is going to look like heading into spring training.

But this year, in an unusually slow market for major league free agents, there is still uncertainty surrounding who will be reporting to Fort Myers, Fla., in a few weeks.

Derek Falvey, the Twins chief baseball officer, said at Thursday night's Diamond Awards banquet that he expects to remain active in free agency.

"We're not done," he said.

Specifically, are the Twins done tinkering with their rotation before pitchers and catchers report Feb. 14?

Manager Paul Molitor called the talent still available "staggering" earlier this week. "There's enough pitching out there, that we can at least deepen our options," he said.

The Twins have already dipped into the lukewarm free-agent starting pitching waters to sign Michael Pineda. But they can still stand to bolster their rotation — Pineda had Tommy John surgery last summer and might not be available the entire 2018 season — and there are plenty of candidates unsigned, including Yu Darvish and 2015 NL Cy Young winner Jake Arrieta.

Darvish and Arrieta, both 31, could not have picked worse times to be free agents. Groupthink has overtaken baseball and teams are hesitant to throw out long-term expensive contracts to pitchers who might not produce at a high level for the duration of their contracts.

You might not think Darvish would be such a prized free agent since he is 17-17 combined ove the past two seasons, but baseball front offices don't use wins and losses to determine a pitcher's worth — at least the smart ones don't. Some of Darvish's advanced numbers, a 3.83 fielding-independent pitching (FIP) mark and, according to the website FanGraphs, 3.5 wins above replacement (WAR), indicate he remains a valuable starter.

FIP is a statistic similar to earned-run average, but it tries to remove defense from clouding a pitcher's evaluation. FIP uses home runs, walks, hit batters and strikeouts — results that don't depend on quality of fielding — in a formula that is a more accurate measure of performance, some say, since a pitcher has no control over how the defense behind him plays.

Darvish's numbers in both statistics placed him in the top 20 in baseball last season, according to FanGraphs.

Below Darvish and Arrieta, the analytics of the top remaining starters suggest there's a mix of value and risk.

Lance Lynn's numbers scream "stay away." The 1.39 difference between his FIP and his ERA last year suggest he was a big beneficiary of good defense in St. Louis. The batting average of balls in play (BABIP) against Lynn was .244, a low number (the figure is usually around .300) that suggests he could be a target for regression next season.

Chris Tillman, who has won 73 games for Baltimore since 2009, is a roll of the dice after shoulder issues derailed his 2017 season. But if a team is convinced it can fix him and get him back to pre-2017 form, the 29-year-old could be a good value.

Another potential value is Jaime Garcia, the lefty the Twins acquired then traded away six days later in July. The Twins are obviously familiar with him. Of the remaining free-agent starters, he is projected to have the third-highest WAR, according to FanGraphs — and he would come at a significantly cheaper price than the two above him in that projection, Arrieta and Darvish. The player fourth on that list, Tyler Chatwood, recently received a three-year, $38 million contract from the Cubs, a reasonable deal given how costly starting pitching can be.

With so much uncertainty in free-agent values, it seems the only thing TwinsFest attendees can be sure of is this weekend is that the team wants at least one more new pitcher onboard when they land in Florida.

Chris Hine is the lead writer for North Score, the Star Tribune's new sports analytics beat. Find his stories at startribune.com/northscore.