After a 2012-2013 offseason that involved two franchise-altering trades, the signing of disgraced-but-effective outfielder Melky Cabrera and a reunion with former skipper John Gibbons, the Blue Jays and their fans hoped that the team would be positioned to make a trip to the post-season for the first time in two decades. The 2013 Blue Jays were so well regarded that they entered the season as Vegas favourite to win the World Series.

Instead, a sell-out Rogers Centre crowd (to which I tried and failed to obtain tickets) was treated to watching new staff “ace” R.A. Dickey surrender four runs in six innings as part of a 4-1 loss to Cleveland.

A year ago the Miami Marlins entered the season with the smallest opening day payroll in baseball ($41.8 M). They ended the season with their best player suffering a gruesome injury and with the lowest attendance in the National League. Their 77-85 record landed them fourth in the NL East.

What a difference an off-season makes. There are a lot of reasons for optimism around Miami heading in to 2015 and what follows is a 2015 season preview for the Marlins.

Are you ready, Marlins fans?

In 2014, the Cincinnati Reds were a tale of two seasons. After a victory over the Pirates on July 13 the Reds were 51-44, and firmly in the playoff race, half of a game out of a wildcard spot, and only 1.5 games out of first place in the NL Central. Well, then the wheels fell off. After that day they were 25-42, finishing with a 76-86 record.

The Brewers, coming off of a monumental collapse to miss the playoffs in 2014, made two major changes over the offseason. First, the team moved Marco Estrada to the Blue Jays for Adam Lind to fill the black hole that has been first base since Corey Hart’s knees failed him in 2013, most recently filled by Mark Reynolds and Lyle Overbay. Second, they traded rotation stalwart Yovani Gallardo to the Rangers for RHP Corey Knebel, SS Luis Sardinas, and pitching prospect Marcos Diplan to bolster their bullpen, infield, and system depth.

The Orioles have been a good, if not great offensive team for three years in a row now. Despite a mediocre ability to get on base, the Orioles finished the 2014 season 9th in batting average, 3rd in slugging, 6th in OPS, and 1st in home runs. The O’s were middle of the pack in getting on base, as many of their full time players are impatient at the plate and embrace a free swinging approach. This approach has worked well for them over the past 4 seasons, averaging 207 home runs, 717 runs, and a .734 OPS per 162 games.

Fans of mediocre teams have, from time immemorial, dreamed of trading all their high-priced talent for prospects, and then “giving the kids” a chance to show what they can do in the majors.  But this is better in theory than in practice, just ask the 1998 Marlins (54 wins) or 2003 Tigers (43 wins).  After losing 106 games in 2011, the Astros hired GM Jeff Luhnow, who promised to rely heavily on advanced metrics to rebuild the entire franchise, from the farm system out.

Injuries poisoned the Diamondbacks’ 2014, so their last-place finish did not necessarily represent the true talent level of the team. That didn’t stop new Chief Baseball Officer Tony La Russa from starting the postseason early by cleaning house. GM Kevin Towers was fired and replaced by Dave Stewart, who played for LaRussa on the late-80s/early-90s A’s. Manager Kirk Gibson and bench coach Alan Trammell were fired the day after Stewart was hired and Stewart later hired A’s bench coach Chip Hale to manage the team for 2015.

The Braves didn’t wait until after the World Series to start their off-season moves, firing general manager Frank Wren Sept. 22nd and naming John Hart interim GM. Hart later accepted the position of president of baseball operations, working with assistant GM John Coppolella. Hart has led a series of trades that saw several key Braves leave town in exchange for prospects and young major leaguers. He acknowledged there was an eye toward 2017, when the Braves will move to Cobb County and open SunTrust Stadium, without trying to ”strip down” the team.