It appears likely — though not yet 100 percent certain — that Giants mainstay Pablo Sandoval is on his way to the Red Sox, and the Giants may look to go a different route recouping the lost value. Ken Rosenthal of FOX Sports spoke to one person with knowledge of the team’s thinking who believed the loss of Sandoval could put San Francisco in play for Jon Lester, and Rosenthal then confirmed with a source that the Giants have indeed shown interest in Lester (Twitter links).

Earlier this morning, reports indicated that Sandoval had agreed to a five-year pact with the Red Sox, but his agents have since publicly stated that no agreement is in place with Boston or any other club at this point. Sandoval will make his decision today, his agent told WEEI.com’s Alex Speier, so we’ll have some closure in the near future.

If the union with Boston does indeed to come to fruition, Lester makes for a logical, albeit more expensive target for Giants GM Brian Sabean (Boston has reportedly already offered Lester $110-120MM over six years). The Giants have little rotation certainty, despite coming off a 2014 World Series victory. Madison Bumgarner is an unquestioned ace, but Jake Peavy and Ryan Vogelsong are free agents. Matt Cain will be returning from elbow surgery. Tim Hudson will be 40 next July, and Tim Lincecum has proven to be unreliable at this stage of his career. Lester could likely be penciled in for 200+ innings and provide some much-needed stability.

Of course, such a pursuit does leave the Giants thin at third base and on the lookout for offense. One other alternative, Rosenthal tweets, would be to pursue Chase Headley. He characterizes a Headley pursuit as “likely” for San Francisco, should Sandoval depart. The switch-hitting Headley would become the prize of the free agent market at third base, and the Giants would no doubt have competition for his services. The Yankees are said to very much want Headley back, but any club that showed interest in Sandoval could logically have some interest in Headley as well. That would include the Blue Jays and White Sox, although to this point, those matches are speculative on my behalf, as there’s yet to be a firm connection to Headley for either club.