So you think you can already name most of baseball's postseason teams for the upcoming season?

Uh-uh. It doesn't work like that.

Major League Baseball has its superteams, for sure. But that doesn't mean there won't be some major surprises. There always are, and that's part of the fun.

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Did you see the D-backs coming this time last year? The Twins?

Let's consider who has the best chance to force their way into the postseason picture this October. One of the best indications is seeing which of the 20 teams that missed the postseason has improved its roster the most in the offseason.

1. Angels

The Angels' improvement actually started on Aug. 31, when they traded for Justin Upton even though he had an opt-out possibility after the season. They extended his deal a year to lock him in, and the arrow has pointed straight up since then.

Few saw the Halos as the likely landing place for Shohei Ohtani, but that's who he picked. His front-of-the-rotation (right) arm is exactly what general manager Billy Eppler's team needed, and Ohtani's left-handed bat could be an underrated part of baseball's most intriguing move. Ohtani fits nicely into a middle-of-the-lineup mix that includes Michael Trout , Upton and Jose Pujols (who enters his age-38 season with four seasons left on his contract).

Eppler has upgraded the lineup through trade -- second baseman Ian Kinsler -- and a free-agent signing -- Zack Cozart, who will shift to third base with Andrelton Simmons emerging as a two-way force at shortstop. The GM just added Rene Rivera as the backup catcher, too.

2. Cardinals

They're a no-brainer on any list of a team that could be headed back to the postseason, as they've had 10 consecutive winning seasons -- including 83 wins in 2017 and 86 the year before. The Cubs grabbed the Cards' mojo by winning the 2015 National League Division Series and are working hard not to give it back any time soon, but any reports of St. Louis' demise were wildly exaggerated.

Manager Mike Matheny's team was better than its record last season, but it was hurt by a weak bullpen (24-29 in one-run games) and the loss of Alex Reyes to Tommy John surgery. The Cardinals have made three major moves in the offseason, trading prospects for power-hitting outfielder Marcell Ozuna and signing free-agent pitchers Luke Gregerson and Miles Mikolas.

President of baseball operations John Mozeliak and his front office probably have at least one more big move, most likely for a closer or a free-agent starter to replace Lance Lynn (who could still re-sign). Don't be surprised if the Cards trade from a surplus of outfielders and young starters to add more pieces to the bullpen.

3. Mariners

First base was a black hole for Seattle last season, but it won't be this time around. The A's were looking at Ryon Healy as primarily a DH option, with Matt Chapman at third base and Matt Olson at first, and did him -- and the Mariners -- a favor by trading him for reliever Emilio Pagan and 17-year-old shortstop Alexander Campos. Along with adding Dee Gordon to play center, that's the most impactful of the usual flurry of moves from GM Jerry Dipoto. What's next?

4. Phillies

It was a surprise when Philadelphia committed $60 million to sign Carlos Santana , but he could turn out to be one of the best values in this market. Rhys Hoskins shifts from first base to left field as part of an outfield that could help contend for an NL Wild Card spot soon. The Phils upgraded the bullpen with the signings of free agents Pat Neshek and Tommy Hunter and opened the door for J.P. Crawford by dealing Freddy Galvis to the Padres.

5. Padres

Speaking of which, Galvis will answer a major question by giving San Diego a proven shortstop to build an infield around until Luis Urias or Fernando Tatis Jr. forces their way into the lineup. The Padres will move up this list if they win the Eric Hosmer sweepstakes, but they have made enough smaller moves -- Galvis, Bryan Mitchell , Chase Headley , Japanese reliever Kazuhisa Makita and Jordan Lyles -- to be on it.

If San Diego does land Hosmer, William Myers could become one of the most productive left fielders around. Closer Brad Hand remains of interest to several teams, but he will only be dealt at a high price. The Padres probably need more time, but they have lots of talent. They could be one of the best stories in baseball if they come flying out of the gate.

Honorable mention: Brewers

The Brewers made the division-rival Cubs sweat last season, but they have made few headlines this offseason, with the addition of Jhoulys Chacin their biggest move. That could change through a trade or a stealth signing of a top free-agent starter, but for now, Milwaukee has done little to improve from its 86-win campaign in 2017.