Spring training is fully underway. The exhibition games have begun, and the light is showing at the end of the baseball-less winter tunnel. The summer ahead promises to be an exciting one for Chicago baseball, but in the next month, there are a few questions to be answered for both the Cubs and White Sox.

These questions are rarely answered during spring training, but even then, it provides at least a look. For instance, Cubs novitiate Ian Happ made a splash during spring training in Mesa last year, and that proved a foretaste of a largely successful rookie campaign last season.

Happ’s team will come into 2018 with a renewed sense of purpose after lavishing in the glory of the 2016 World Series championship for at least the first half of last season and boasting a sub-.500 record at the All Star break as a result. Though the Cubs surged in the second half to win the division and reach the championship series for the third year in a row, a four-games-to-one NLCS beating from the Dodgers made for an anticlimactic finish.

Much has changed about the Cubs since last October, so these are the things to keep an eye on this spring:

How will the revamped bullpen fare?

Last year’s closer, Wade Davis, blew only one save and waited until the regular season was nearly over to do it, and his strikeout of Bryce Harper for the final out of Game Five of the division series against the Nationals was probably the highlight of the Cubs postseason. But he is gone now, so a glaring question for the Cubs of 2018 is how well this new bullpen will perform.

Brandon Morrow and Steve Cishek are the newcomers, and both come with equal cause for excitement and anxiety.

Morrow, 33, is a bit of a journeyman—the Cubs are his fifth team since debuting in 2007—but he had a career year in 2017 with the Dodgers. The hope is that he can continue the success that led to a nearly 30 percent strikeout rate, 2.06 ERA, and zero home runs allowed as the team’s likely new closer.

The problem is, Morrow has never been a closer for a full season, so if he falters, Cishek is the replacement. The latter was a pretty dominant ninth-inning pitcher for the Marlins in 2013 and 2014, and he saved 25 games for the Mariners in 2016. But Cishek threw only 44 innings last season, splitting his time between the Mariners and Rays, so whether he can show some of that old form is uncertain.

What should Cubs fans expect from the new rotation?

Jake Arrieta and John Lackey are gone, and in their place, Yu Darvish and Tyler Chatwood have arrived. At a glance, this is an upgrade, but one that will hinge on Chatwood.

Darvish is largely a known quantity, and despite his World Series struggles, probably a slight improvement over Arrieta going forward. The Cubs will get their greatest value—potentially—from Chatwood, who had uninspiring overall numbers in 2017, but his home/road splits hint that he will be a much better pitcher away from Coors Field in Denver, the most pitcher-unfriendly stadium in the majors. Last year, his home ERA was 6.01, but on the road it was 3.49, and in 2016 his 1.69 road ERA was the best in baseball.

Even if he pitches somewhere between these numbers, Chatwood will make for one of the best fifth starters in the game.

Can Kyle Schwarber find his potential at the plate?

The catcher-turned-left fielder landed a home run on top of Wrigley’s right-field scoreboard during the 2015 NLDS and then made a heroic return from injury for the 2016 World Series, only to come to a screeching halt at the plate last season. Through June 21 he was hitting .171 and headed for Triple-A Iowa to rediscover his swing.

Schwarber hit .253 in the second half of the season and was particularly hot in September, but time will have to tell if what plagued him in the first half of 2017 will continue.

The Cubs offense is well-rounded enough to absorb another subpar season from Schwarber, but a large part of the difference between battling for the division title and locking it up early could come down to him.

On the south side, the White Sox have entered the second phase of their rebuild, according to GM Rick Hahn, and this season will be important for the development of their cadre of uber-talented prospects. Here’s what lies ahead for them in 2018:

What does the next phase of the rebuild look like?

During the fan convention in January, Hahn emphasized the need for patience, both among the fans and within the organization. The allure of going for it is hard to resist, but for the White Sox, this summer will be mostly about enjoying the firsthand look at the growth of young players like Yoan Moncada, Carson Fulmer, and Lucas Giolito.

Moncada was the biggest return in the December 2016 Chris Sale-to-Boston trade, and at 22, he is years away from his probable prime, but the future is bright. Fulmer, the 2015 first-round pick, came up late in the season and pitched back-to-back quality starts on September 10th and 15th. Similarly, Giolito, who came from the Nationals in exchange for Adam Eaton, joined the rotation in late August and pitched extremely well, including a ten-strikeout start against the Rays on September 3.

All three should have full seasons in Chicago this year, so the biggest wins for the White Sox might not come in the standings but in their major league development.

Whose debut comes next?

As if the three players mentioned above weren’t enough, the White Sox will enter the 2018 season with one of the top farm systems in baseball, and they are set to graduate a few more into the majors this year.

One of these is outfielder Eloy Jimenez, once a pearl in the Cubs’ system before they swapped him for Jose Quintana. This trade is one of those rare instances where both teams stand to benefit mightily, and White Sox fans will probably get a firsthand chance to see why this summer.

Hahn has been somewhat coy about what 2018 will hold for Jimenez, but he has been consistent in leaving open the possibility of a major league debut. If that happens, gird the outfield lights at U.S. Cellular Field. During the High-A Carolina League home run derby last June—just a month before he was traded—Jimenez brought the fictitious Roy Hobbs to life when he hit the lights with one of his prodigious bombs.

And set to join the aforementioned Fulmer and Giolito, Michael Kopech should be bringing his triple-digit fastball to the American League sometime this season. Kopech, who also came to Chicago in the Chris Sale trade, pitched most of 2017 in Double-A, but he made the jump to Triple-A Charlotte at the end of last season, where he struck out 17 batters in 15 innings, so the remaining rung for him to climb is the one to the majors. When he arrives, whether it’s on the Opening Day roster or sometime later, Kopech will be a formidable addition to the pitching staff.

Are the White Sox done trading?

A major piece of the success in stocking the farm system has been swapping as much of their major league talent as possible, as painful as it might have been for the fans. But Sale brought Moncada and Kopech, Eaton brought Giolito, and Quintana brought Jimenez and Dylan Cease, not to mention the returns for Todd Frazier and David Robertson, so Sox fans are not likely to remember that pain for long.

And should they choose, the front office could keep going. Jose Abreu would be an appealing trade piece for a lot of teams, and Avisail Garcia’s breakthrough 2017 season has made him a viable option as well.

But realistically, the trades were the first phase of the rebuild, and for now the White Sox are done dealing. They value Abreu for his leadership too much to let him go at the price that other teams would likely offer. Garcia was a revelation last season, hitting .330 and shrinking his strikeout rate, and at just 26 when this season begins, he is worth keeping.

Both teams have reason for excitement this spring, but both come with important questions. The Cubs can add another World Series trophy to a collection that sat stagnant for over a century if the bullpen breaks right and Schwarber mashes up to his potential, and the White Sox can accelerate their rebuild if they hold on to established players like Abreu and Garcia and even just a few of the young players from their swarm of prospects pan out.

That means that, on both sides of town, Chicago is in for a fun summer.