Pitcher Alex Cobb and the Tampa Bay Rays are officially going separate ways.

Cobb did not accept Tampa Bay's qualifying offer, and will officially hit the free-agent market, Marc Topkin of the Tampa Bay Times reports.

Cobb will look for a multi-year deal in the open market this winter after declining the $17.4 million offer, which comes on the heels of earning just $12.2 million combined during the last three years with the Rays.

The 30-year-old started 29 games this past season, and recorded a 3.66 ERA and 1.22 WHIP, with a 128:44 K:BB over the course of 179.1 innings.

Wherever he winds up, Cobb will be a key cog in that organization's rotation.

On Thursday, Cobb published a message to Rays fans, thanking them for their support.

"Your words of encouragement meant so much to me during the highlights of my career, but they meant even more during the challenging ones," he wrote.