The Gunners take on their West London rivals in the second leg of the Carabao Cup semi-finals on Wednesday, 24 January, and Arsene Wenger had revealed earlier in his press conference that the duo were doubtful with tests planned for both of them.
Ramsey missed Arsenal's 4-1 win over Crystal Palace on Saturday, 20 January, after picking up a knock during the loss against Bournemouth the previous week, but was pictured training with the first team on Tuesday, 23 January. He is likely to start from the bench with Jack Wilshere and Granit Xhaka currently occupying his place in the Gunners' midfield.
Monreal, on the other hand, came off after 34 minutes with a suspected hamstring injury against Crystal Palace and Wenger had rated him as a doubt for the game with Antonio Conte's side. The defender, however, confirmed that he had recovered from his minor knock and is ready to take his place at left-back on Wednesday night.
"Speedy recovery, time for the semi-finals," Monreal wrote on his official Twitter account, confirming his return to the squad.
The north London club will be without injured duo Olivier Giroud and Danny Welbeck, who are still sidelined with the manager stating that they are fractionally short. The France international striker has reportedly begun light training and could return by the end of the week.
Meanwhile, Arsenal's high-profile January signing Henrikh Mkhitaryan took part in his first training session with the squad on Tuesday. However, he is not eligible for the game after having played in the Carabao Cup for his former employers Manchester United.
The Armenian midfielder is likely to make his debut for his new club when the Gunners travel to the Liberty Stadium to take on Swansea on 30 January.