Roberto Di Matteo appears intent on bolstering the Chelsea squad this summer, as the Blues attempt to build off their Champions League and FA Cup titles in a very busy summer transfer period.

Chelsea are currently in the U.S. for the World Football Challenge, and played to a 1-1 result with Paris Saint-Germain in front of 38,202 at Yankee Stadium in New York on Sunday night. The Blues received a late goal from Lucas Piazon off a fine assist from Ramires to even the match in what was at times a sloppy performance. Chelsea were without Fernando Torres, Daniel Sturridge, and Juan Mata, among others.

While the Blues' roster looked rather thin on Sunday, Chelsea are expected to have reinforcements soon.

Brazilian midfielder Oscar took a medical with Chelsea, and has been linked to a £25 million move to Stamford Bridge. Internacional president Giovanni Luigi made a statement to Radio Guiaba that the two clubs have a deal in place, but Oscar claims that he hasn't signed anything.

I only had a meeting with the doctor, nothing else, Oscar said, according to ESPN. I didn't sign any contract yet and I will wait until the end of the Olympic Games to decide my future.

The 20-year-old has featured with Brazilian Under-20 squad, and has six appearances for the senior squad. Before joining Internacional, he had a brief stint with Sao Paulo.

While Oscar's move to Chelsea seems likely, another Brazilian midfielder's status is not so clear. Shakhtar Donetsk manager recently said that the club turned down Chelsea's £26.5 million bid for Willian, who has been with the club since 2007.

I don't know what the coach said, but the correct value is [£19.5 million], said Willian to Globo Esporte. Regardless of the price, it is clear that the desire is great to play at a club like Chelsea, the champion of the Champions League.

I'm really upset with the board for not letting me leave. It would be good for me and also for the club. I'd be in a big city and have the chance to grow professionally. This is not a message to anyone - everyone knows I want to leave.

Talks have also apparently faltered with Borussia Dortmund striker Robert Lewandowski. Chelsea's £17 million offer for the 23-year-old was rejected, according to an ESPN report.

Lewandowski is under contract until 2014, but the Polish star has expressed interest in playing in the Premier League. According to The Times, Tottenham are interested in challenging Chelsea for Lewandowski.

Chelsea are also involved in bringing in 21-year-old winger Victor Moses from Wigan Athletic in a £10 million move. Thorgan Hazard, the younger brother of recently signed Eden Hazard, is on the club's radar, as well. There have also been discussions of Belgian international Romelu Lukaku being loaned out.

Meanwhile, Frank Lampard didn't rule out a potential move to the U.S. to play in MLS when he spoke to reporters outside the locker room at Yankee Stadium. There had been reports linking the veteran midfielder with the Los Angeles Galaxy, though Lampard later rubbished that speculation.