"It's just another opinion to see if we're on the right page," Giants manager Bruce Bochy said, referring to Cain's appointment with Andrews. Cain also might consult Dr. David Altchek, the Mets' medical director, while the Giants play a four-game series in New York beginning Friday.
The Giants have multiple reasons to worry about Cain, 29.
As the senior Giant in terms of continuous service, Cain has established himself as one of the pillars of the club. His durability, which he demonstrated by pitching 200 innings or more each year from 2007-2012, seemed almost given.
Thus, the mere thought of Cain having his arm cut open chills the front office. At this juncture, surgery would almost certainly end his season.
Though Cain has pitched with loose bodies in his arm in recent years, his performance dipped dramatically this season. He went 2-7 with a 4.18 ERA in 15 outings after beginning the year as the Giants' No. 2 starter.
Since Cain made his Major League debut with the Giants on Aug. 29, 2005, against Colorado, he has thrown the fourth-most regular-season pitches among all Major League hurlers -- 29,037. That doesn't count the 2010 and 2012 postseasons in which he excelled.
The three starters ahead of Cain on this list, Detroit's Justin Verlander (31,337), Seattle's Felix Hernandez (29,818) and Los Angeles' Dan Haren (29,724), have dealt with either diminished velocity or inconsistency.
The Giants have made a significant investment in Cain, who signed an eight-year, $139.75 million deal before the 2012 season. He's slated to earn $20 million annually through 2017. The Giants hold a $21 million option on his 2018 contract and will owe him a $7.5 buyout if that option is not picked up.
The sense that Cain could remain unable to pitch for an extended period led the Giants to obtain veteran starter Jake Peavy last Saturday from Boston for Minor League pitching prospects Edwin Escobar and Heath Hembree.
The mere fact that Cain is seeing Andrews is likely to prompt speculation that he'll need Tommy John elbow surgery, which typically requires at least one full year of recovery time. But Bochy emphasized that such a judgment would be premature.
Indeed, pitchers who endured maladies similar to Cain's recovered at different rates.
Philadelphia ace Cole Hamels had loose bodies removed from his elbow after the 2011 season and was throwing again by December.
Toronto's Sergio Santos underwent surgery in mid-May last year for removal of bone chips and spurs. He was activated from the 60-day disabled list Aug. 1. As a reliever, however, Santos might not be fully comparable to Cain.
Tampa Bay's Jeremy Hellickson had loose bodies removed Jan. 29 of this year, made his first injury rehabilitation start June 7 and returned to the Majors on July 8.
Angels left-hander C.J. Wilson needed elbow surgery after the 2012 season. He returned in 2013 to build his winningest record (17-7).
Then there was the case of St. Louis' Chris Carpenter, who needed Tommy John surgery after removal of bone spurs. Those spurs helped stabilize a ligament.
So the Giants might have to keep holding their collective breath after Cain leaves Andrews' office.