By Arsenal correspondent Tony Hughes

Arsenal were given a major defensive boost as they made their final preparations for Sunday’s FA Cup quarter-final clash against Watford.

Football Insider sources have learned that Per Mertesacker, Gabriel, Hector Bellerin and Laurent Koscielny all took part in full training on Saturday.

Mertesacker and Gabriel have overcome injury scares, Bellerin is back and Koscielny is in contention to return after three matches on the sidelines with a calf injury.

It gives Arsene Wenger options as he prepares the team ahead of a pivotal few days in which the Gunners host Watford in Sunday’s quarter-final before travelling to Barcelona in the second leg of a last-16 Champions League tie and then a trip to Everton in the Premier League title race.

Mertesacker, Gabriel and Aaron Ramsey were all forced off during the 4-0 FA Cup win at Hull on Tuesday night.

Speaking on Friday at his media briefing, Wenger said he was confident the centre-back pair would be available for selection to face Watford.

“Gabriel and Mertesacker should be available,” the manager said. “Koscielny is not far and will have a test on Saturday. Bellerin is available.”

However, Wenger delivered less optimistic news on the condition of Aaron Ramsey as he admitted that, as revealed by Football Insider on Wednesday afternoon, the midfielder is set for a lengthy spell on the sidelines.

Asked if Ramsey could be out for the rest of the season with the thigh injury he sustained at Hull, Wenger said: “I don’t think that. The clinical signs are quite positive. I would say four weeks.”

Ramsey joins Petr Cech on the sidelines as well as long-term absentees Alex Oxlade-Chamberlain, Jack Wilshere, Santi Cazorla, Tomas Rosicky and Carl Jenkinson.