The 2012 Blue Jays finished with a 73-89 record, and a 74-88 Pythagorean Expectation. Offensively, they ranked 24th in baseball with a 15.8 fWAR, and 28th in pitching behind a 7.6 fWAR. Theoretically, a team like this would need to add at least 22 additional wins to start thinking about a playoff run, and that's exactly what GM Alex Anthopoulos did. They've arguably had the biggest offseason, thus far. They've lost Yunel Escobar (1.8 fWARin 2012), Jeff Mathis (0.8), Kelly Johnson (0.7), Carlos Villanueva (0.6), Henderson Alvarez (0.5), Brandon Lyon (0.4), Jason Frasor (0.2), Adeiny Hechavarria (-0.2), Yan Gomes (-0.2), and Omar Vizquel (-0.6). In total, it's only a loss of 4 fWAR, leaving the team at a 70-92 record for 2013. This is, of course, before we factor in all the additions they made in free agency and trades.
In free agency, they signed both Melky Cabrera (4.6 fWAR in 2012) and Maicer Izturis (0.7). They did their real damage in trades, and acquired R.A. Dickey (4.6), Jose Reyes (4.5), Josh Johnson (3.8), Mark Buehrle (2.1), Esmil Rogers (0.8), Emilio Bonifacio (0.6), Josh Thole (0.1), Jeremy Jeffress (0.0), and Mike Nickeas (-0.6). Assuming each of these players repeats their 2012 season, this is an additional 21.2 fWAR to their team. In theory, this should add 21 wins to their 70-92 record, giving them a projected 91-71 record.
There are still a number of factors that this ignores. For instance, the Blue Jays were the third most injured team in the American League in 2012. Players like Brandon Morrow and Jose Bautista could have been the team's leading pitcher and hitter in wins, had it not been for injuries. They also have a number of very young players that are beginning to reach their prime years. The downside to the moves this offseason, is that the players they acquired also have questions surrounding them. Jose Reyes and Josh Johnson have legitimate injury histories, Mark Buehrle hasn't played well against the American League East, Melky Cabrera might not be the same player when he stops using performance enhancing drugs, and R.A. Dickey is 38 years old.
If everything goes right, you can add a few wins on top of that 91 win benchmark, perhaps bringing the team to close to 100 wins. However, realistically, this is a low-90 win team, and preliminary ZiPs projections has them at 93-69. While this is the best pre-season projection the Blue Jays have had in a while, they have as much downside as any contender out there. So many of their pieces are high-risk that it's hard to count on the team as a favorite come April.
Though it seems that the Blue Jays have runaway with the AL East, the Rays, Yankees, and Red Sox aren't far behind them. ZiPs has Tampa at 88 wins, the Yankees at 87 wins, and the Red Sox at 85 wins. Any of these teams are a couple moves behind the Blue Jays to bump their projection to the mid 90's. The Yankees, in particular, have a designated hitter and catcher to add to their roster, and likely another outfielder, before they take the field in April.
This isn't to assume that the Blue Jays are done spending, but it looks like the Yankees, Rays, and Red Sox are just inches behind the supposed AL East favorites, and there's a lot more to be done this offseason.