CHICAGO -- There's no No. 49 on the Cardinals' roster. Not yet, anyway.
But imagine the angst at Wrigley Field in April if Jacob Arrieta pops up wearing his familiar number, this time around pitching for St. Louis.
This possible twist would be the latest in one of baseball's best rivalries, which recently has seen both the Cards and Cubs aggressively poaching talent from the other team's roster. It could happen.
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That's not all.
As an extra touch, how crazy would it be if Arrieta just happened to be facing Yu Darvish?
That could happen, too. Darvish might land a bigger contract from the Cubs than their best offer to Arrieta, even though the powerful right-hander -- the man who pointed to a taste for kale and Pilates as helping him go 12-1 with an 0.75 ERA in the second half of 2015 -- was a key to winning the '16 World Series.
For Theo Epstein and the Cubs' front office, the memory of Darvish dominating for the Dodgers over 6 1/3 innings in Game 3 of the National League Championship Series is fresher than any of the multiple highlights from Arrieta's five seasons on the North Side.

Arrieta is five months older than Darvish. He's marketing himself as a free agent as he heads into his age-32 season, two years older than Max Scherzer when he landed his $210 million deal from the Nationals. Darvish will pitch at 31 for most of next season.
Arrieta lost almost two mph off his fastball last season, dropping from an average 94.3 to 92.7. Darvish's velocity has ticked upward since he missed the 2015 season because of Tommy John surgery. His fastball averaged 94.9 in the second half of last season.
Velocity's not everything, as the Astros showed when they pounded Darvish twice in the World Series.
Arrieta pitched to a 2.28 ERA in the second half last season, then held the Nationals and Dodgers to one earned run over 10 2/3 innings in the postseason. When the Cubs were eliminated, he packed up his family from the Wrigleyville home he had rented and headed home to Texas, not expecting to be re-signed.
Since winning the NL Cy Young Award in 2015 with a historic second-half performance, Arrieta has been open about his belief that his next contract should be for seven years. That's the length given to Scherzer, Justin Verlander, Clayton Kershaw, Carsten Sabathia, David Price, Felix Hernandez, Masahiro Tanaka and Stephen Strasburg.
While the Cubs love Arrieta, they never embraced the idea of an extension because of his desire to be guaranteed a big commitment through his age-38 season. They remain in contact with him and agent Scott Boras, but seemingly only on shorter deals.

Reports have linked Arrieta to the Cardinals, Brewers, Nationals, Phillies, Rangers and even the Rockies (never mind the 14.54 ERA in two starts at Coors Field). The St. Louis tie bears watching given not only the rivalry but the recent history between the two teams.
In Joe Maddon's first season in Chicago, the Cubs went 45-18 down the stretch to grab an NL Wild Card spot. Their biggest feat was beating the Cardinals in the NL Division Series, and after doing that they signed two of the key Cardinals to play for them.
Jason Heyward and John Lackey rode alongside William Fowler in the ensuing World Series parade. The Cubs loved Fowler, their center fielder and leadoff man, but they weren't willing to give him a big contract entering his age-31 season. The Cardinals stepped up to sign him to a five-year deal, in the hope he'd lead them back to the postseason after they missed by a game in 2016.
Instead last year was an even bigger disappointment, with the Cardinals slipping to 83-79. It was their 10th consecutive winning season, but they finished four games behind the Rockies, who won the NL's second Wild Card spot.
While the Cubs won a second straight NL Central title, their victory total dropped from 103 to 92. The Cardinals believe they can catch them this season, which is why they traded prospects to the Marlins for outfielder Marcell Ozuna and have signed free-agent pitchers Luke Gregerson and Miles Mikolas (after three strong seasons in Japan).
The Cardinals have at least one more big move in them, maybe two.

Signing Arrieta could make it easier to use their surplus of young pitchers and outfielders to deal for a third baseman like Manny Machado or Josh Donaldson, perhaps with a late-inning reliever like Brad Brach or Roberto Osuna in the package.
The Cardinals could decide to leave the rotation as is and sign a free-agent bat. They've been linked to both Eric Hosmer and Mike Moustakas.
That's intriguing, but it's not like imagining Arrieta in a Cardinals' uniform. It might not feel like Game 7 of the World Series every time he faced the Cubs -- maybe just Game 5 or 6.