After finishing in ninth position last term, Brentford are hoping to assemble a squad that can build upon a successful campaign.
They have already made an impression in the transfer window, signing Dutch goalkeeper Mark Flekken from Freiburg.
Kevin Schade has also arrived from the German club on a permanent deal after spending the second half of last season on loan at Thomas Frank's side.
The Bees recently completed the signing of South Korean youngster Kim Ji-soo, who will link up with the Brentford B team.
Despite being busy in the early stages of the window, Brentford are still determined to add to their squad, and they are keen to strengthen the centre of their defence following Pontus Jansson's departure.
A recent report claimed that Brentford were working on a deal to sign Collins from fellow Premier League side Wolves.
According to Football Insider, the Bees are now close to signing the Republic of Ireland international after achieving a breakthrough in negotiations.
Brentford have seen several bids knocked back by Julen Lopetegui's side, but the two clubs are on the verge of reaching an agreement.
Collins joined Wolves from Burnley for a reported £20.5m fee last summer, and he featured regularly in the first half of the campaign, but he fell down the pecking order following the arrival of Craig Dawson in January.
Despite falling out of favour, the central defender made 31 appearances across all competitions last season, helping Wolves steer clear of the relegation zone.
Wolves are reluctantly set to part ways with Collins, as they look to raise funds to help meet Financial Fair Play regulations.
The Midlands club have already generated significant income this summer with the sale of Ruben Neves, who recently completed a £47m transfer to Saudi Arabian club Al-Hilal.