The Philadelphia Phillies are preparing a considerable offer to their soon-to-be-free-agent left-hander Cole Hamels in the next two weeks in an attempt to sign him to an extension.  

Though terms of the offer haven't been disclosed, ESPN's Jayson Stark referenced two deals that may set Hamels' value: the five-year, $112.5 million extension given to the San Francisco Giants' Matt Cain, and the five-year, $120 million pact the Phillies gave Cliff Lee in December 2010.

Although the Phillies' payroll is approaching the $178 million luxury-tax threshold, the club believes it can find a way to keep Hamels under the threshold in 2013 and beyond.

Hamels, 28, said earlier this week that he'd consider staying with the Phillies, but also would like to test the free-agent market and find out his true worth.

"Every human being wants to know what their value is, in whatever job they're doing. If you get to do it, it's a pretty cool experience." Hamels said while addressing the media before the All-Star Game this week.

With Hamels wanting to test free-agency, that's an indication to the Phillies to offer free-agent market dollars-and years-if they hope to keep him.

The Phillies, however, have their options to trade Hamels before the deadline if they can't come up with a deal, and then likely make another attempt to sign him in the off season.

The Texas Rangers have been prominently mentioned as the favorites to trade for Hamels if the Phillies deal him. But other clubs have expressed their interest, but are willing to bid their time, waiting for signals that the Phillies seriously intend to trade him and that the initial price tag, of four or five premium young players, has come down.

Hamels potentially appeals to a long list of contenders that include the Dodgers, Tigers, Pirates, Red Sox, Cardinals and Reds.

The Phillies, however, won't have a serious focus on potential trades until they can determine whether their view of Hamels' market value matches his own.