#2 Willian (Chelsea)

Willian is a 30-year-old right winger who currently plays for Chelsea in the Premier League. He has also featured a total of 63 times for Brazil since his debut in November 2011.
With the Brazilian now in his 30s, getting picked for the first team will become much harder than before. On paper, anyone entering this decade is on their way to retirement and set to be replaced by the younger, more energetic players vying for his spot.
At the moment, however, he's still featuring in a lot of games for the Blues, with 27 appearances under his belt so far this campaign. But with only three goals and six assists to his name, there isn't much to shout about. A player as key to the attack as he is should be doubling those stats at the very least by this point.
With that in mind, Chelsea could likely be open to offers for Willian this summer, and that's where Barcelona come in. The club is eager to bolster their attacking options for next season, which is where Willian could flourish for them. La Liga is significantly easier than the hard-hitting Premier League, so it may be the ideal place for him to go next.