James Shields is eligible to hit free agency after the 2014 season.
James Shields is eligible to hit free agency after the 2014 season. (USATSI)

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Royals ace James Shields appears set to be one of the most attractive free agents on the market next offseason, assuming he doesn't sign a contract extension to stay in Kansas City. And it sounds like the Royals better hurry if they intend to take this course of action.

Shields appeared on former general manager Jim Bowden's Sirius XM radio show Tuesday. And he said the following:

Shields was one of the worst starters in 2010, leading the majors in hits and earned runs allowed while also leading the AL in home runs allowed. Since then, though, he's been outstanding.

In the past three seasons, Shields has gone 44-31 with a 3.15 ERA (124 ERA+) and 1.15 WHIP. He's averaging 235 innings pitched and 215 strikeouts per season in that stretch. Last year, he led the AL in starts, innings pitched and batters faced. So it's fair to say he's become one of the best workhorses in the league.

After coming over in a blockbuster trade with the Rays, Shields led the Royals to their best record since 1989 -- as they went 86-76.

Shields, 32, could join the likes of Jon Lester, Max Scherzer and Justin Masterson as top-flight starting pitching options to hit free agency after this season. Lester really wants to stay in Boston and it sounds like he'll eventually stay put. Masterson and the Indians are reportedly discussing an extension and Masterson himself was quoted as saying he figured he'd stay put. On the flip side, keeping Scherzer sounds like it'll be a real challenge for the Tigers, and Scherzer also won't talk extension during the season.