The unofficial start to the 2015 baseball season started this past week with the Winter Meetings in sunny San Diego, California and the hot stove is roaring with many teams making moves to better their rosters in 2015 and beyond.

The Chicago Cubs landed perhaps the biggest starting pitching free agent this off-season, signing former Boston Red Sox star Jon Lester to a six-year, $155 million dollar contract – the largest in franchise history – to become the ace of the Cubs staff for new manager, Joe Maddon.

To the south, the cross-town rival Chicago White Sox made big moves as well, inking former Yankees closer David Robertson to a four-year deal worth a reported $46 million. Robertson, a Baseball Factory alumnus, saved 39 games for the Bronx Bombers in 2014, pitching to a 3.08 ERA and striking out 96 batters.

They acquired talent in the starting rotation as well, trading for starter Jeff Samardzija from the Oakland Athletics in exchange for four players. The A’s received infielder Marcus Semien, RHP Chris Bassitt, catcher Josh Phegley and first baseman Rangel Ravelo.

Samardzija, the former standout at the University of Notre Dame in football, won 26 games as a starter for the Cubs before being traded at the deadline last season.

Out west, the Los Angeles Dodgers are making a major push to be the team to beat in the N.L. West in 2015 with a flurry of trades to improve the ball club.

All-Star second baseman Dee Gordon was acquired by the Miami Marlins in a seven-player deal that saw Marlins top pitching prospect Andrew Heaney go to the Dodgers. Gordon batted .289 with a .326 on-base percentage and should take full advantage of the spacious dimensions at Marlins Park in 2015.

To replace production lost in the Gordon trade, the Dodgers then packaged Heaney to the Los Angeles Angels for veteran second baseman, Howie Kendrick. Kendrick provides more power to the lineup, hitting .293 for the Angels in 2014, knocking in 75 runs.

Dodgers President of Baseball Operations Andrew Friedman wasn’t done yet, acquiring former Philadelphia Phillies shortstop Jimmy Rollins for two minor league pitchers. Rollins, the Phillies all-time hits leader, brings veteran experience to the Dodgers lineup.

The latest report is that the Dodgers and San Diego Padres have a deal in place to send outfielder Matt Kemp to the Padres for catcher Yasmani Grandal, pitcher Joe Wieland and another prospect. Kemp hit 25 homers and drove in 87 runs for the Dodgers last season.

Mat Latos, who won 33 games in three seasons with the Cincinnati Reds, was shipped to the Marlins for right-hander Anthony DeSclafani and catching prospect Chad Wallach.

The Reds moved another starting pitcher out of their rotation, sending Alfredo Simon to the Tigers for right-hander and 2013 first-round draft pick, Jonathon Crawford and infielder Eugenio Suarez. Simon provides depth and experience in the Tigers rotation, winning 15 games in 32 starts last season in Cincinnati.

The #WinterMeetings kept everyone on edge until its final moments: http://t.co/iLWYeBL7Gy pic.twitter.com/0pu85Aj9cv

— MLB (@MLB) December 11, 2014

Starting pitcher Rick Porcello, another Baseball Factory product, was traded by the Detroit Tigers to the Boston Red Sox for slugger Yoenis Cespedes. Porcello won 76 games in six seasons with the Tigers.

Boston wasn’t done adding to the rotation, signing former Cleveland Indians starter Justin Masterson to a one-year deal worth $9.5 million, re-joining the team that drafted him in 2006.

Wade Miley is reportedly moving from the Arizona Diamondbacks to the Red Sox as well, involved in a four-player deal that sends Rubby De La Rosa, Allen Webster and a minor leaguer yet to be named to Arizona. Miley has pitched over 200 innings the last two season for the Diamondbacks, winning 18 games during that time period.

Ervin Santana has reportedly reached an agreement with the Minnesota Twins on a multi-year deal worth $55 million. Santana signed a one-year deal last season with the Atlanta Braves and went 14-10 with a 3.95 ERA in 31 starts.