Historically, the summer transfer window in MLS comes at an awkward time. Not only does it fall midseason — a difficult proposition for selling key players abroad unlike Europe's top leagues — but for much of the league's recent history it has also closed in early August.

Thankfully, both issues will be alleviated when MLS aligns with Europe and flips its calendar to summer-to-spring. Buying and selling should become smoother, or at least create less of a headache than, say, Real Salt Lake losing Zavier Gozo to Crystal Palace halfway through the season. MLS this year shortened its winter window and extended its summer window, meaning the transfer window remains open until Sept. 2. There is still plenty of time for clubs to make key signings and, as is typical in Europe, more players will soon be available.

These are the three teams to watch over the next few weeks.

Colorado Rapids

Fresh off a historic deal that sent Lucas Herrington to Hull City for up to $23 million, Colorado Rapids president Pádraig Smith vowed the club would reinvest and not let the opportunity go by. Colorado can add a designated player and a couple of U-22 initiative signings this summer if it does nothing else. There might be additional changes to the current roster, with Smith insisting the club needs to be bold if it must.

The Rapids beat Sporting KC 2-0 this weekend as DPs Rafa Navarro (one goal) and Paxten Aaronson (one assist) led the way, though the game-winning goal came from a set piece again. Reliance on set pieces and being better against set defenses is the main goal for Colorado this summer. Head coach Matt Wells has brought a possession-based, high-energy system, and a lot of players fit well — but the team could do with another key addition or two.

The team is top five in possession but lagging in xG (23rd in MLS) and goals (16th). A winger will be at the top of the wishlist. The club has been linked with highly rated Israeli forward Sayed Abu Farkhi and talks are advanced, according to sources who spoke under condition of anonymity because they are not authorized to discuss the matter publicly. But there's no guarantee that a deal happens, as the club works through several plans to execute this summer.

Chicago Fire

The Chicago Fire also have an open DP spot following the departure of Hugo Cuypers to CF Monterrey — interestingly enough, Cuypers still is tied for the Golden Boot lead in MLS — and are expected to use it. The Fire has a pretty set and well-drilled team under Gregg Berhalter, and the team is among the best in the East, though a clear level below Nashville SC and Inter Miami.

Though Robin Lod has been fine and André Franco will return from a torn ACL before the year ends, the Fire are primed for a DP No. 10 to go along with the addition of Robert Lewandowski earlier this summer. Money is not an obstacle, as the club's ownership has among the deepest pockets in the league, the front office has an excellent recruiting team and the coaching staff a defined playstyle. Chicago could vault themselves much closer to the top of the East with one big signing.

St. Louis City

St. Louis City already brought in DP attacker Carlo Holse from Samsunspor for $6 million earlier this summer, but with Marcel Hartel leaving, they can add another DP. They remain in the market for a DP No. 9. The club came close to signing Cuypers from Chicago, but the Belgian opted for Monterrey, and the club continues that chase in a remade team under head coach Yoann Damet.

St. Louis beat San Jose 3-1 this weekend, continuing their run as one of the hottest teams in the league. City is unbeaten in 10 games across all competitions and has won five of their last six, climbing to fifth in the West. Further departures can come as well, including fan favorite Eduard Löwen. The club has received inquiries from other clubs in the league, plus some simmering interest abroad. Contract talks between Löwen and the team have not yielded positive results and a summer exit is possible.