#2 Kostas Manolas
AS Roma have been on a downward spiral this season. Despite reaching the club's historic- semifinal run in the previous edition of the Champions League, the Italian giants got knocked out by Porto in this season's round of 16 ties and could also be out of Serie A's top 4. This situation could boost Arsenal in their pursuit of Kostas Manolas.
Manolas has been regarded as one of Europe's best defenders in recent years and, he would be the definite answer to Arsenal's struggling defense. Laurent Koscielny has already hit past his 30 while Shkodran Mustafi struggles to provide decent protection for the team.
The Greek defender is a fast, robust and all-around defender who could stop the opposition from creating dangerous counter-attacks. Arsenal is an offensive-minded club that loves to dominate their opponent; hence the 27 years old would fit seamlessly into the system.