The coronavirus pandemic made the summer transfer window very different from its predecessors but, with football back on the agenda, the January window will open as normal for Europe's top leagues.

Though clubs spent nearly €1.5 billion less ($1.9bn) in the summer than they did the previous year, according to FIFA, a number of deals were agreed in October to be completed as soon as the winter window opens. January is traditionally a quieter month, but will the global events see some different strategies for the top sides?

Here are the grades for all the major deals. The most recent write-ups are at the top; each day is in order of highest price. If you don't see a grade for a move that has been completed, check back later. All fees are reported unless confirmed with *.

JAN. 4

SEAD KOLASINAC
Loan

Arsenal: C
Schalke: B+

Schalke are a mess and need all the help they can get after a winless run of 13 games in the first half of the Bundesliga. Bringing back a former player is a good start, while handing him the captaincy despite the fact he's only on loan for the rest of the season is a clear sign something isn't right. He will want to impress and can certainly help them.

Arsenal are taking a bit of a gamble on the fitness of Kieran Tierney. The Scotland defender has been excellent this season, but one injury and the Gunners may have an issue without Kolasinac. Left-back options would then be Bukayo Saka, who is better used further up the pitch, and Ainsley Maitland-Niles, who is more comfortable on the right or in midfield. Kolasinac was clearly frustrated about his lack of playing time (and probably also with his friend Mesut Ozil being frozen out), but letting him go in a season with more injuries than most could prove costly.

JAN. 2

AMAD DIALLO
€21m (£19m, $25.5m)

Atalanta: B
Man United: B

*Deal still pending announcement of work permit

With only a handful of games under his belt for the Italian side, the October announcement that Diallo would move to Man United came as quite a shock. Atalanta brought the 18-year-old through their youth ranks and clearly rated him highly, but an offer of €21m, with another €20m possible in add-ons, was too good to refuse. It's possible they could have held out for another few years to see how he develops, but nobody would begrudge them taking the money in the current climate.

United are taking a gamble but their transfer policy is geared toward young players and they landed one of the most exciting wingers around. It would be a surprise if Diallo went straight into the first team, but they did well to hold off competition for a player they have tracked for a year after he impressed in the UEFA Youth League. It's a lot of money, but at least half the outlay is based on performance.

DOMINIK SZOBOSZLAI
€20m ($24m)

FC Salzburg: B
RB Leipzig: A

The relationship between the two Red Bull-owned clubs made negotiations here pretty simple, as it's a well-worn path for players. It's possible that Salzburg may have been able to get more money for the Hungary midfielder, but they will bank the cash and move on to developing their next young talent.

Szoboszlai had courted attention from some massive clubs, including Arsenal, Milan, Bayern and Real Madrid. So Leipzig did incredibly well to persuade the 20-year-old that he should continue his development in Germany. It's probably the perfect club for him, as the style of play is similar to that of Salzburg and the Bundesliga has a reputation for enhancing the skills of young players. Expect to hear a lot more about Szoboszlai in the coming years.

FILIP STEVANOVIC
€8m (£6m, $9.75m)

Partizan Belgrade: C+
Man City: B-

Partizan took the unusual step of announcing the deal with Manchester City in October without City actually confirming anything, so there remains an element of doubt over this one. The 18-year-old winger is clearly highly rated by the Serbian club he joined as a 9-year-old, as he made the breakthrough into the first XI this year after moving through the youth teams. Partizan will bank the €8m plus add-ons but may regret letting Stevanovic go so early in his career.

City's scouts have seen something in the teenager, though it's likely Stevanovic heads out on loan (potentially back to Partizan) for the rest of the season. While he cites Cristiano Ronaldo as his role model for style of play, he's still far too inexperienced to make a dent in City's first-team squad. They did well to beat off a reported 15 clubs -- including Manchester United, Real Madrid, Liverpool, Bayern Munich and Chelsea -- for his signature, but he's clearly one for the future.