Thomas, 29, has penned a loan contract at the Coral Windows Stadium this Friday which will keep him in Phil Parkinson's squad until the end of April.
Subject to receiving the relevant clearances, Thomas could now be in line to make up part of City's match-day squad for Saturday's Fleetwood fixture.
The striker will wear squad number 39 during his time at Valley Parade.
Speaking about Thomas' arrival, Parkinson said: "We are delighted to have brought Wes here.
"He is a player who likes to run in behind, he's played well off target men in the past.
"We've looked at his record when he has played alongside Alex Revell at Rotherham and other target men, and he has done well. He is a player who suits what we need at the moment - he is a good fit.
"We are confident he will be a good acquisition for us. We needed a lift, we know that, and sometimes the players themselves need a lift from a fresh face or two coming into the building.
"Wes fits the criteria of what we are after. When you speak with a player, you get an idea of them straight-away.
"I liked his desire to come up here in the first place and his determination to get himself going again."
Thomas has already enjoyed a loan spell in Sky Bet League 1 this season with Swindon Town earlier in the campaign.
Along with his time with Swindon, Thomas has also featured for AFC Bournemouth and Portsmouth at League 1 level.
The potent forward has plenty of experience playing Championship football as well, having represented Birmingham, Rotherham United and Blackpool in England's second tier.