AS Roma current performance quit well under Daniele De Rossi in domestic league and Europe League, I have the same optimistic with you how potential AS Roma would be qualify to semifinal round for defeating AC Milan on quarter final match.
Since arrived Daniele De Rossi, AS Roma tactical change drastically from more defensive become team more offensive and aggressive for scoring as many possibility goals every match.
Current Milan's performance still not consistency yet I think not problem for Daniele De Rossi continue the winning trend in Europe League, last match Roma failed taking three points after holding draw by Lecce and its bad thing get race fourth position standings and Roma have motivate for qualifying to Champion League next season.
Initially I started to be optimistic about AS Roma in the Europa League. But I started having doubts after
seeing that Roma could only get a draw in yesterday's match in Serie A against Lecce. I think there is a change that occurred where in the match against Lecce it seemed that Roma had difficulty building attacks. I hope it's just a test of De Rossi's strategy. And I hope that in the match against Milan in the Europa League quarter-finals we can see Roma with the improved quality of their attacks like when De Rossi first arrived at the club.
There are different strategies in every match. I think De Rossi is working on different strategies. They can play against Milan with a style of play that they do not expect because Milan is analyzing them now based on the fixed tactics they play. If Rome plays with a surprise tactic, they can catch Milan off guard, but of course this tactical change has a price. If they don't play well, Milan could destroy them.

De Rossi wasn't a creative coach. He was a monotonous coach who repeatedly used the same strategy and i have observed it based on the last matches and i take a conclusion that if acmilan probably playing offensively against roma caued by pioli may feel so confident to beat roma with playing offensively like what it did in the last match against roma. I'd like to point out how de Rossi consistently uses 4-3-3, as opposed to the image above, which shows when Roma being coached by Foti and it was losing against acmilan with huge margin, rossi will be kinda different with foti but let's see. I predict that there will be no significant changes to the Roma. The club will use a 4-3-3 offensive against Acimlan.
The main issue with Acmilan is that it frequently uses 4-2-3-1, whereas Roma can use the same offensive strategy of 4-3-3, but it can also be fully concentrated on defenseive too. Totally depends on Roma's strategy for the first leg that will happen soon.