This year, the Mets expect the right-handed-hitting Tatis to platoon at first base with the left-handed Daniel Murphy, though he could also back up corner outfielders Jason Bay or Jeff Francoeur in a pinch.
Tatis' presence has made it overwhelmingly unlikely that the Mets will pursue free agent Carlos Delgado, whose fourth -- and likely final -- season with the Mets ended in hip surgery.
Tatis, who won the 2008 Comeback Player of the Year Award after a one-year hiatus from professional baseball, is a .266 hitter with 111 home runs over a 10-year career with the Cardinals, Expos, Orioles and Mets.
The Mets also added a bit of depth with Fogg, who will compete with Fernando Nieve and Jonathon Niese for the fifth starter's role in Spring Training. Fogg, 33, spent last season in a relief role with the Rockies, posting a 3.74 ERA in 24 appearances, one of them a start.
His pedigree is that of a starter. Before last season, Fogg had started 193 of the 219 games he had appeared in with the White Sox, Pirates, Reds and Rockies. He has a 62-69 career record and a 5.03 ERA.
With the Mets, he will enter into a fifth-starter competition that also includes Nieve, whom manager Jerry Manuel this week called the favorite to win the job, and Niese, who will only make the team if the Mets are sure he has fully recovered from last season's hamstring surgery.
Should Fogg lose the competition, he could still slot into the bullpen as a long man.
With five of their top six starting pitchers coming off injury, the Mets could use some rotation depth. They were reportedly interested in both Joel Pineiro and Ben Sheets, before those two signed with the Angels and A's, respectively. And they reportedly remain interested in John Smoltz, another injury risk who has the most upside of any of the remaining free agents.