The Sydney Morning Herald broke the news, calling it "one of the biggest coaching bombshells in the history of the game".
Quoting "sources familiar with negotiations", Marshall is reportedly already helping to calm any fears had by Eels second rower Isaiah Papali'i, who had been pondering a contract backflip.
Marshall and Farah were both part of the Tigers' 2005 premiership success and will now be tasked with rejuvenating the club despite minimal coaching experience between them.
Marshall had been working with some younger players via a consultancy role and had reportedly been hesitant to get involved with the NRL side under Maguire.
However, earlier in the week when he was first linked to the role, Marshall appeared keen to join the coaching ranks.
Asked if he'd be willing to coach the Tigers, Marshall said it would be the only team he'd want to coach.
"Obviously it's been reported that Tim's going to get the job and he's going to mentor someone," Marshall told NRL360 earlier in the week.
"If the opportunity for me to be mentored under him with a pathway to become a head coach, it's something I'd definitely consider.
"I love my job, what I do now (as a commentator at Fox League), but that's an opportunity I might never get again, the opportunity to try and become a head coach.
"For me, an NRL head coach is a dream job and to be mentored by someone like Tim and learn underneath him with a chance to get there, if that's the route they want to go down with me, it's something I'd be interested to explore, for sure."
NRL 360's Paul Kent pointed out Marshall has limited coaching experience and would have to deal with the Tigers' administration, which has been heavily criticised for its decision making in recent years.
But the 37-year-old responded: "Yeah, I am ready. The reason I am ready is you don't actually know until you hit that pressure gauge whether you are ready.
"The thing I've always done is I back myself."
Marshall had previously left the Tigers twice, choosing to leave the first time after 201 games for the Tigers, trying his hand at rugby with the Blues, an ultimately ill-fated move which saw him return to the NRL.
After reasonably fruitless stints at the Dragons and Broncos, Marshall returned to the Tigers in 2018, until he was unceremoniously moved on under Maguire.
"If anything I was a bit disappointed the way I found out, reading it in the paper. That was a little bit disappointing for me," Marshall said on Fox League's NRL360 at the time.
"I had a good chat with the coach; he laid out where I stood. I appreciated the honesty, I can finish the season and then both parties will move on.
"When you hear about not being wanted through other sources that are not the coach or the club you want to find out if it's true or not, so I went in there and asked if it's true or not. He asked for 24 hours to give me an answer, and the answer came back I won't be required."
But Marshall finished his NRL career in the grand final, coming off the bench for the South Sydney Rabbitohs in the 2021 decider loss to the Penrith Panthers.
