Would Chicago Cubs Trade with Arch-Rival to Solve Key Infield Question?

The Chicago Cubs appear to be willing to give Matt Shaw, their No. 1 prospect, every chance to win the third base job during spring training.
In some way, the Cubs really need him to win the job. A look at their MLB.com depth chart shows two veterans at third base — Vidal Bruján and Jon Berti. At a position that demands power, neither has shown consistent power in their Major League careers.
Alex Bregman signed with the Boston Red Sox earlier this week. The Cubs reportedly made a four-year, $115 million offer with opt-outs. The Red Sox snagged him for $120 million for three years, with opt-outs.
Bregman would have been a snug fit at third base. Now, the Cubs are hopeful that Shaw can fill the role.
But there is another option — but Cubs fans may not like it.
Nolan Arenado has been seeking a trade this offseason, but to this point he hasn’t found a taker. The soon-to-be 34-year-old would be a great addition to the lineup. He’s an eight-time All-Star and a 10-time Gold Glove winner. He’s won five Silver Sluggers at third base and six Platinum Gloves.
He’s also led the National League in home runs three times. He has the power and the glove to give the Cubs security at the hot corner.
He’s also a St. Louis Cardinal, and that’s the problem. ESPN's Buster Olney wrote that the Cubs and Cardinals would be a "theoretical fit" for a deal.
The Cubs and Cardinals are long-time rivals, of course. They will play each other more than a dozen times because they’re in the same division. Their bitter rivalry dates back to the late 1800s. In fact, they met in the 1885 and 1886 World Series, the precursor to the modern World Series when they were the Chicago White Stockings and the St. Louis Browns.
It’s safe to say the two fan bases don’t get along.
But there’s another issue. Teams in the same division try to avoid trading with one another, lest one make the other team better.
The Cubs and the Cardinals have made deals with each other before. According to History of Cardinals, St. Louis once dealt Todd Zeile to the Cubs in 1995. The Cubs notably sent reliever Bruce Sutter to the Cardinals in 1980, who later helped them win a World Series in 1982.
For the deal to work the Cardinals would likely charge the Cubs a premium for their division proximity. There is also the matter of Arenado’s salary, as he’s owed more than $50 million, with a $75 million luxury tax charge, the next three seasons.
And the two sides would have to put their rivalry aside. That could be asking too much.