Manchester United seem likely to be without Wayne Rooney for four weeks, while Cesc Fabregas's season will be over if his suspected broken fibia is confirmed.
Rooney, the Premier League's leading scorer with 26 goals, seems certain to miss United's three biggest remaining domestic fixtures, the games against Chelsea on Saturday, against Manchester City on Apr 17, and Tottenham a week later.
Fabregas, Arsenal's leading scorer with 15 goals, will also be badly missed by an Arsenal side already without Robin Van Persie. But the problems don't end there, with Andrei Arshavin also out for three weeks, and William Gallas struggling to play again this season.
Chelsea's title odds have shortened considerably since the weekend, coming in from 12/5 to 11/10 with some bookmakers.
And though Chelsea have suffered their own injury problems, losing Ashley Cole, Michael Essien and Ricardo Carvalho, their squad appears more robust as the home straight approaches.
"We are disappointed to be out of the Europe, but it could help us," said Carlo Ancelotti last week.
"The quarter-finals use a lot of energy not only physically but mentally At this moment in the season to have one more point or one less point is not so important. Every team Arsenal, Manchester United and Chelsea needs to win their games. If you are in good condition, mental and physical, you can win.
"So it's not more important to have one more or one less point. It's important to stay fit and have optimism and confidence to win the game."