“Everyone who knows AFL footy knows Ben Johnson and what he’s done,” Farrelly told The Leader.
“He’s class off-field as well, the character he is … he’s fitted in very well and he’ll be awesome for our boys just with that experience.
“My first thoughts were that he’s in phenomenal shape. He has certainly been in the gym and – in his words – getting back to peak fitness to the level he’s able to at his age.
“He trained last night, trained really well and was pointing guys in the right direction.
“We have a little intraclub once a week which he participated in, and he was moving well and got his hands on it a few times.
“It’s nice to see him run around and the boys definitely noticed his presence straight away.”
Johnson has ties to the Magpies through nephews Zac, Luke and Nathan Reichelt.
Farrelly said he was unsure how many games the 39-year would play but that his leadership impact was equally important.
“He hasn’t played proper local league football in a few years, so he will do the training, a couple of praccy games and just see how the body’s feeling,” he said.
“He’s got a few outside commitments as well … but we’ll see how he feels and let him dictate (his availability) a little bit.
“Obviously it will be a minimum of one (game), but the maximum, who knows.”
Johnson averaged 17.6 disposals and four marks over his 14 years in the AFL before hanging up the boots at the end of 2013.