NEW YORK -- San Francisco Giants executive VP Brian Sabean has quietly been at Citi Field during the Mets-Nationals series, multiple sources told ESPN.com.

The reason for the presence of Sabean as well as senior advisor Lee Elder at the Queens ballpark is not clear, although Sabean did relinquish the role of general manager to deputy Bobby Evans last month and resolves to do more scouting in the field.

The Giants could be looking to upgrade at third base this summer. Casey McGehee is hitting .164 with one homer and two RBIs in 16 starts at the position.

And the Mets happen to possess an available third baseman, with Daniel Murphy coincidentally having just shifted to the position in David Wright's absence. Murphy is in his final season before free agency. And the Mets already have Dilson Herrera ready to take over at second base, making Murphy expendable once Wright returns from a right hamstring strain.

Still, Mets officials in recent days have suggested there is nothing serious going on right now involving Murphy and discussions with other teams.

The Mets also have an excess starting pitcher, which may be another Giants need before the trade deadline. San Francisco's Ryan Vogelsong and Tim Lincecum have struggled, while Jake Peavy and Matt Cain are on the DL, possibly for the long term.