Terry, who has recently battled through a torturous court case following a nightclub incident back in January (from which he was cleared of any wrong doing), has already clearly outlined his ambition and intentions for both club and country stating, “At the first opportunity, I will be banging on the door to England and I will grab the chance, if it comes, with both hands.”
That was not the only major problem affecting the former England Under-21 international - as a summer knee operation ruled him out of the Blues' opening seven games this season.
The Barking-born defender played the first half of last night's 2-0 reserves victory against Arsenal at Barnet - a match in which 19-year-old midfielder Joe Keenan broke his leg.
The good news for Chelsea, however, is Terry is now in line for his first-team return against the struggling Hammers.
Terry's off-field problems have delayed his promotion from England's Under-21s to Sven-Goran Eriksson's senior side - but Ranieri, asked if he felt Terry is ready to make the step up, said: “Yes, I think so.
“Everything, good or bad, makes a man mature. John's had a bad experience, but an intelligent man changes a bad thing into a good thing.
“John is an intelligent man - but everybody has something they do when they're young. I'm sure what happened was very bad for him, but it's impossible that it will happen to him again.
“John's a strong man and needs more training sessions until he's back to top form. I'd say a maximum of a month from now.
“He's getting fitter and played last night, so he's on the bench tomorrow - although I cannot say if he will play.”
Terry's return coincides with the emergence of 18-year-old German defender Robert Huth, who starred in his debut Premiership start, against Fulham in Monday's 0-0 draw at Loftus Road.
Terry and Huth face fierce competition from Marcel Desailly and William Gallas. And Ranieri has formulated a plan to accommodate all four in his team - limiting them to 25 games each this season.
“The real problem is when I don't have enough players,” Ranieri said. “Maybe I won't play Desailly, Huth or Gallas - what I'll do is play two good players.
“It's open and I like a good fight between my players. Everyone wants to play, but we'll play a lot of games this season.
“It's important to make sure the players have good condition, both psychologically and in their stamina. We didn't stay very, very strong at the end of last season because we were tired.
“I don't want that to happen again so maybe my players will play 25 or 30 games a season rather than 45 or 50."
Chelsea are third in the early Premiership table, while Saturday's opponents West Ham remain rooted to the bottom with just two points.
Ranieri added: “It's unbelievable they don't have more points, as they're a very good team. They've been unlucky at the moment, but sooner or later that will change.
“I've watched them twice and know it will be a very, very difficult match tomorrow as they'll be furious.
“They have very skilful players like Joe Cole, Paolo di Canio, Trevor Sinclair and Freddie Kanoute.”