The Roma midfielder picked up an untimely knock during the Azzurri's quarter-final clash with England on Sunday.
He was forced from the field 80 minutes into that game with a sciatic nerve problem.
Italian medical staff were due to carry out tests on Monday in an effort to determine the severity of the injury.
It remains unclear whether De Rossi will be ready for a last-four encounter with Germany on Thursday.
The combative 28-year-old is refusing to give up hope regarding his possible participation, but concedes that he faces a race against time to prove his fitness.
"I hope to recover in time for the semi-final," said De Rossi. "The sciatic nerve is causing me pain and right now I am not optimistic."
Borussia Dortmund hears Wembley Calling and are headed to London for the Champions League final.
The push for more color on their cleats, adidas has added the infrared colorway to the adiZero f50 Line.
The Juventus jersey for the 2013/14 was released earlier this week. Be the first to wear the colors of the Old Lady.
adidas has added some color to the Predator line with this new colorway. Released on May 17. Be the first to own a pair.
Chelsea won the Europa League on Wednesday. The Blues defeated Benfica 2-1 on injury time goal from Ivanovic.
The adidas Nitrocharge is the most talked about new cleat in years. It was released on May 15 and will take your pitch by storm.
The new PUMA evoSPEED 1.2 FG. A great new soccer cleat with classic look and first time for PUMA to be on the cleat.
One of the top soccer cleats for control the Nike CTR360 will not let you down on the field in tight spaces.
Ajax has released their away soccer jersey for the 2013/14 season. Get in the Gear.
The Liverpool 2013/14 soccer jersey is available for pre-order. The Reds are eager to compete for silver next season.