Demba Ba could make his Chelsea debut in Saturday's FA Cup match against Southampton after completing his move from Newcastle to Stamford Bridge.
Ba, who for an undisclosed fee, trained with the club on Friday.
Manager Rafael Benitez said: "He's fine so he has a chance to play."
Ba failed a medical with Stoke in January 2011 because of a chronic knee problem but Benitez said there was "no problem" with the striker's medical.
"We know the situation," said the Spaniard.
"This is a player playing in the Premier League and playing every game and he can play [every game] for us."
It is believed Ba's contract with the Magpies contained a clause allowing him to speak to other clubs in the event of a £7m bid.
The new signing will be eligible for selection for Saturday's match at Southampton and the Capital One Cup semi-final against Swansea, but is not available for Chelsea's Europa League campaign, having appeared in the competition for the Magpies.
"It feels good to be here. I'm very happy and very proud," the 27-year-old told the Chelsea club website.
"It was important for me, and for Newcastle, to get my future sorted and now we can move on.
"When the club who won the Champions League wants you, the decision is very easy. This club is massive and that's something that helped the decision a lot. It was not a hard one."
Ba, who moved to Newcastle from West Ham in June 2011, replaces Daniel Sturridge, who left Stamford Bridge to join Liverpool this week.
Ba has scored 13 league goals for the Magpies this season. His arrival will help alleviate the burden on £50m frontman Fernando Torres.
The 28-year-old Spaniard has scored 14 goals this season, seven of them in the league.