The players they had this past season, they havent paid for a bunch of them yet. This summer they pay for Mancini, Veretout and Carles Perez which is 40 million euros. So they have those commitments, another 22 million euros to keep what they had this year for Smalling - maybe they figure thats too much with corona going on.
I would say its a bad move because if everyone is fit they have a good midfield and attack and score goals, its balancing their defense that will be key for them to go to the next level next season. Maybe they get Verthongen on a free and that lets them buy a younger player to try to help the defense. Are they going to do as well as Smalling did? Probably not, but Roma probably wants some resale value. They only bought Dzeko and Kolarov for 11 and 5 million euros and they're two of their best players, so maybe they're looking for cheap players like that again