Here is a chart showing the number of home runs hit by the Mets in all of the full months of last season and so far during spring training.
Twelve of the Mets home runs this spring training have come from players who will likely not make the team (Chris Carter, Ike Davis, Fernando Martinez, Omir Santos and Russ Adams).
Nine of the home runs have come from players that will likely make the 25-man roster, but were not on the team last year (Jason Bay, Mike Jacobs, Gary Matthews Jr. and Rod Barajas).
Stats from Baseball-Reference and Mets.com