Yes IF Santana has another career year AND Berrios improves AND Mejia improves markedly AND Gibson's last two months were for real AND a young arm does emerge AND there are no injuries whatsoever THEN yes you could get away without adding an impact starter. That doesn't mean you should!
I typically root for Atlanta teams. Too many similarities between our cities: 1. NFL teams have suffered tremendous playoff heartbreak and no super bowls. 2. Baseball teams that were dominate in the regular season for long stretches but not enough corresponding playoff success. 3. NBA teams that have only rarely been relevant. (Not a huge NBA fan) 4. Both cities lost a hockey franchise.
Oh okay... and what happens to the DH? Are we really ready to start baseballs holy war? Would prefer 8 4-team divisions, aka NFC North (MIN, MIL, CHI, DET).
Vargas sticking with the team next year as a sub .800 OPS 1B/DH depends on if anyone (Palka, Park... maybe even Rooker) challenges him for his bench spot. Could also be made redundant in FA.
Aside from some World Series heroics, nothing helps Mauer out more than winning a gold glove this year. "Only player to win a gold glove at catcher and in the infield" that's just made for the plaque. I think he needs 2-3 more years of quality at bats and another gold glove to get in. Hard to gauge how much voters will value his time at catcher, but he'll have a strong case.
What does the bullpen look like next year? You've got Hildy, Busenitz, probably Duffey and Rogers. I know most are in favor of bringing Pressly back. FA guys like Gee and Belisle have been very good to us. You think about bringing them back right? But then you are already at 7! Do you really want to roll with the same bullpen? If you sign a FA who is the odd man out there? And thats counting on nothing from Moya/Curtiss/Reed (or May / ORourke ...) and you've likely got to stash Hughes in there as well.