Free-agent signings, offseason trades, the Rule 5 draft, preseason signings and trades, difficult cuts before the season, waiver claims, the MLB draft, international free-agent signings, timely promotions of top prospects (or decisions to not call up a prospect), in-season trades and a busy non-waiver trade deadline, waiver trades, preparing for September call-ups …

It has been a long run for major league general managers, but they're about to the point they can sit back and let things play out. The Aug. 31 waiver trade deadline is almost here, bringing with it the finalization of rosters for postseason eligibility. But that doesn't mean the roster you see on Sept. 1 is the roster the team will have for the playoff run. Not only are there inflated rosters to go with September call-ups, but we're looking at the possibility of several key players returning to their teams -- not to mention prospects who could be important to their team's success. These final moves can be the difference-makers for teams making the playoffs, winning their division or even getting to the World Series.

With that, here's a look at how playoff contenders are setting up their rosters for the race -- in many cases directly from the front offices themselves.

National League

St. Louis Cardinals: The Cardinals will be getting significant players back from the disabled list over the next couple weeks. It will start with first baseman Matt Adams, who is expected to begin a rehab assignment Monday, with outfielders Jon Jay and Randal Grichuk not far behind. Outfielder Matt Holliday is expected to return sometime in mid-September. Holliday, Adams and Grichuk will immediately return to the middle of the lineup, with Jay likely falling into a backup role behind Jason Heyward, Holliday, Grichuk and Stephen Piscotty. One interesting note: Cardinals manager Mike Matheny is open to Heyward playing some center field down the stretch to get Piscotty more playing time.

Then comes the final surprise piece: pitching ace Adam Wainwright, who is coming back from an Achilles tear in April. Wainwright came jumping into Matheny's office this week and said his arm feels the best it has ever felt. GM John Mozeliak said it was "a big if" when I asked him if Wainwright would pitch again this year; and if it happens, he said it will be in a relief role. However, Matheny gives the impression he's not betting against Wainwright. He told me Wainwright has been saying he'll be returning this year to start, not relieve. I also wouldn't bet against Wainwright returning -- as a starter or reliever -- by mid-September.

Pittsburgh Pirates: Pirates GM Neal Huntington told me