If Major League Baseball had a system or relegation and promotion, like in club soccer... ignoring the fact that, for the moment, there are no non-U.S. teams in the International League, and most of the teams in the Pacific Coast League are nowhere near the actual Pacific Coast:
The Indianapolis Indians had the best record of any Triple-A team, with a .618 winning percentage, winning the International League West Division. They would be promoted to take the place of the Houston Astros, who finished last in the National League Central Division. (That's the I-Indians' cap, above.)
The Sacramento River Cats had the next-best record in Triple-A ball, with a .597 winning percentage, winning the PCL Pacific Southern Division -- one of the divisions left over after the merger between the PCL and the now-defunct American Association. The River Cats would be promoted to take the place of the Seattle Mariners, who finished last in the American League Western Division.
The Scranton/Wilkes-Barre Yankees, in spite of not having a home field all season due to their ballpark being renovated -- PNC Field was originally built to resemble Veterans Stadium, as the team was a Phillies farm club called the Red Barons, and it's going to look like a real ballpark by Opening Day of next season -- finished .583, leading the IL North Division. They would be promoted to take the place of the Miami Marlins, who finished last in the NL Eastern Division.
The Charlotte Knights had a .576 winning percentage, winning the IL South Division. They would be promoted to take the place of the Boston Red Sox, who finished last in the American League Eastern Division. That's right, "Red Sox Nation" and (N)ESPN, your Chowdaheads would have been relegated to Triple-A!
The Omaha Storm Chasers had a .576 winning percentage, winning the PCL American Northern Division, made up of former AA teams. They would be promoted to take the place of the Minnesota Twins, who finished last in the AL Central Division.
The Reno Aces won the PCL Pacific Northern Division, at .563. The Albuquerque Isotopes (formerly the Albuquerque Dukes) won the PCL American Southern Division, at .556. Having the 2 worst records among the Triple-A Division winners, they would face each other in a one-game Playoff, for the right to replace the Colorado Rockies in the NL Western Division.
New York Yankees
Tampa Bay Rays
Toronto Blue Jays
Chicago White Sox
Kansas City Royals
Omaha Storm Chasers
Los Angeles Angels of Anaheim
Sacramento River Cats
New York Mets
Scranton/Wilkes-Barre Red Barons
St. Louis Cardinals
Western DivisionArizona Diamondbacks
Los Angeles Dodgers
San Diego Padres
San Francisco Giants
Nice setup for rivalries between Oakland and Sacramento, which might help boost attendance in Oakland; between Kansas City and its Triple-A club Omaha; and between Indy and both Chitown and Cincy.
Of course, this could never happen, because none of the current Triple-A teams has a ballpark with a seating capacity greater than 25,000 -- most are in the 10-to-12,000-seat range. These teams simply couldn't afford to boost their ballparks to major league standards. It also doesn't help that these teams are all part of "farm systems," and might have to face their "parent clubs." Some Triple-A clubs even have the same names as their parent clubs, which is why the Scranton team would have to go back to their former name, an amalgamation of two old-time minor league clubs, the Scranton Red Sox and the Wilkes-Barre Barons.