It's been a busy MLS offseason thus far, with plenty of big money flying around as clubs around the league look to beef up their rosters ahead of their 2020 campaigns.

With preseason just around the corner, here's a look at the five biggest transfers we've seen this break so far.

Lucas Zelarayan

We'll start with the most recent arrival in Zelarayan, who is officially headed to Columbus Crew SC following the announcement that the club has acquired the Argentine attacker from Tigres UANL of Liga MX for a club-record transfer fee that will reportedly exceed $7 million.

It's a hefty price tag, but the 27-year-old is coming to Crew SC in his prime and was a key attacker for a Tigres side universally considered one of the strongest in all of North America.

Zelarayan also fills an obvious area of need following the departure of Federico Higuain, one of the most productive and dynamic No. 10s that has ever graced the league. That's a big void, but Tim Bezbatchenko and Co. clearly believe they have their man to provide some pinpoint service for Gyasi Zardes and finish off a few goals himself.

Alan Pulido

The need for a ruthless No. 9 has followed Sporting Kansas City for what seems like forever now, and coming off a disappointing 2019 campaign, the clamoring for that elusive, carry-the-load goal-scorer only increased. In Pulido, who signed with SKC for another club-record transfer fee earlier this month, the hope for club brass is that the search is finally over.

Another Liga MX veteran, Pulido has 57 goals to his name in Mexico's top flight across stints with Chivas Guadalajara and Tigres, as well as five goals in 13 senior caps for Mexico. He's the kind of player many SKC followers believe the club has needed to reach the next level.

Cristian Espinoza

Espinoza in action for San Jose in 2019. | USA Today Images

Matias Almeyda's San Jose Earthquakes were one of the surprises of the league last season, nearly nabbing themselves a playoff spot after finishing dead last in the Western Conference in 2018.

A key contributor to that turnaround is now in MLS to stay, with Espinoza agreeing to a multi-year Designated Player contract earlier this month following yet another club-record transfer fee.

It was an important move for continuity's sake, as Espinoza was San Jose's top provider in 2019 with 13 assists in 2,533 minutes. Almeyda will want to see him score more goals in 2020 than the two he hit in 2019. If he does, he could be one of the league's more lethal dual-threat attackers.

Lucas Cavallini

Much like SKC, the Vancouver Whitecaps have struggled to find a reliable option up top, cycling through veterans like Kei Kamara and Fredy Montero. At the same time, their attack became among the least productive in MLS with 37 goals last season.

In Cavallini, Vancouver fans hope they've found the man to change all that. Cavallini has become a fixture for Canada's national team with 11 goals in 17 caps. At the club level, he has reached double-digit goals nearly every calendar year wherever he's been ahead of his transfer to the Whitecaps from Puebla of Liga MX.

Vancouver still have some work to do to fill out their roster, but Cavallini should at least bring up that goal total, and it'll be interesting to see how he combines with talented young playmaker Inbeom Hwang, a bright spot in 2019.

Adam Buksa

Bruce Arena's overhaul continued with the announcement that the New England Revolution were bringing in Polish striker Adam Buksa on a Designated Player contract.

The 23-year-old has spent his entire pro career in Poland's Ekstraklasa, netting 18 goals in 40 appearances for Pogon Szczecin in his most recent stop. Provided his skillset transfers to MLS, the move makes a Revs attack that already features some potent options in Gustavo Bou and Carles Gil even scarier.