The 4 best trade deadline moves in Cardinals' franchise history

The Cardinals trade for one of the best home run hitters in baseball history in 1997.

Mark McGwire was well into his 16-year career by the time he came to St. Loius, but the extreme heights he would eventually reach were still to come when the Cardinals acquired him via trade during the 1997 trade deadline.

The Oakland Athletics had little hope of re-signing the then 33-year-old, and they were hoping to milk the trade value he had left despite him being on the wrong side of the aging curve in baseball. At the time of the trade, the Cardinals sat at 51-55, well behind the division-leading Houston Astros (yes, for a time there were six teams in the National League Central and only four in the American League Central. Go figure).

This wasn't a trade where the Cardinals were trying to improve an already strong lineup; rather, they were hoping McGwire would provide the boost that the lineup needed. Mark would be a free agent at the end of the season, so the Cardinals were playing with fire when they sent three young players in T.J. Mathews, Eric Ludwick, and Blake Stein to Oakland. Mathews had a 2.62 ERA as a reliever in his first two seasons, Eric Ludwick was ranked 13th among pitching prospects in baseball, and Stein was a serviceable depth starter at the time.

What St. Louis got in exchange was more than they could imagine. Not only did McGwire bring winning back to the city soon after his arrival following some disastrous decades, but he also helped grow the sport with the great home run race of 1998. None of the players whom the Cardinals sent to Oakland ended up performing well for the organization, and the lopsided results of this deadline deal make it one of the best in the organization's history.

The Cardinals give up quite a bit to land Scott Rolen in 2002, but it pays off.

This trade is actually a bit more balanced than the others on this list, but Scott Rolen's place as a part of the "MV3" in St. Louis makes the scales tip in favor of the Cardinals. In order to land the hot corner maestro, The Cardinals had to send Placido Polanco, Mike Timlin, and Bud Smith to the Philadelphia Phillies for Scott Rolen at the 2002 trade deadline.

Placido Polanco went on to have a great career, and despite only playing in Philadelphia for three total seasons, he was able to accumulate nearly 10 fWAR in that time. Polanco was a premier infielder for his time. Mike Timlin didn't provide much value to the Phillies, and Bud Smith was out of baseball soon after the trade.

Scott Rolen would go on to play five and a half years in St. Louis, win a World Series in 2006, accumulate 27.2 fWAR, attend four All-Star Games, and receive three Gold Glove Awards. Rolen's best year of his career came in 2004 when he had a 1.007 OPS, a 158 OPS+, 34 home runs, 124 RBIs, and a Gold Glove. He would finish fourth in National League MVP voting that year. Rolen was elected to the Hall of Fame last year.

Rolen's heights, consistency, and defense made this deal one for the ages for the Cardinals. They sacrificed a steady infielder in Polanco, but what they got out of Scott Rolen in his peak years was matched only by his teammates, Jim Edmonds and Albert Pujols. His contributions to the 2006 World Series team were essential, and this trade will go down as one of the best deals at the deadline for the franchise.

The Cardinals land Matt Holliday in another lopsided trade with the Oakland Athletics in 2009.

Oakland should be wary when trading their stars to the Cardinals at this point. For the second time in about two decades, St. Louis was able to snag a perennial All-Star while sending players back to Oakland who wouldn't pan out. This time, it was for an outfielder: Matt Holliday. Holliday would become a cornerstone in St. Louis for many years after this deal.

In what was one of John Mozeliak's biggest moves early in his tenure as general manager, St. Louis sent Clayton Mortensen, Shane Peterson, and Brett Wallace to the Athletics for corner outfielder Matt Holliday. At the time, this deal was a bit risky. Brett Wallace was one of the best prospects in baseball, and Clayton Mortensen was rising in the Cardinals' farm system. Peterson was a recent second-round draft pick.

Sending three young players with full team control to Oakland for an outfielder who was a free-agent-to-be was quite bold. If Holliday were to sign elsewhere, the trade would be maligned by fans. If any one of the prospects panned out to be as good or better than Holliday in St. Louis, the trade pendulum would swing dramatically in the other direction.

Instead, this deadline deal from 2009 couldn't have gone better for the Cardinals. Wallace was a below-average hitter with poor defense, Mortensen struggled to maintain a major league roster spot, and Petersen wasn't even a replacement-level hitter for his career.

Meanwhile, Matt Holliday would garner MVP votes in four of his seven seasons in St. Louis and go to four All-Star games. Holliday was also awarded a Silver Slugger trophy in 2010 with St. Louis. Some of Matt Holliday's best years came in St. Louis, and the lack of production from the players who went to Oakland made this deal at the deadline one of the best in St. Louis history.