Wait, he was a Red Sox pitcher?
Starting Pitcher: John Smoltz (2009)
It doesn't feel right that John Smoltz qualifies for this team, but I assure you it happened. I vividly remember being down in Aruba in 2009, watching a Red Sox-Orioles game at Smokey Joe's where the Sox blew a 10-1 lead, and John Smoltz had gotten the start that night. It's the lasting memory I have of the 2009 Red Sox, mainly because I got a really cool Smokey Joe's t-shirt that night.
Back to Smoltz, the first-ballot Hall of Famer made 8 appearances for the Red Sox in 2009, embarking on his lone year outside of Atlanta in his career (Smoltz would join the Cardinals for the rest of the 2009 season after being released in August). Honestly, Smoltz should have been a Brave for life, but for the purposes of best team possible, I'll take him as the ace any day.
Honorable Mentions: Picture this as the rest of the rotation behind Smoltz: David Cone, Bartolo Colon, Bret Saberhagen, and either one of David Wells or Brad Penny. I often wish that some of these 5 would be a part of the current Red Sox rotation over some of our current options, but these ghosts shall mingle together forever in this dream scenario.