Manchester City said Richards suffered a shin injury in their win at Middlesbrough on Saturday, while Woodgate picked up a knock in Boro's FA Cup replay defeat at Manchester United on Monday.
"We are assessing Micah daily, we hope by the weekend he will be okay," McClaren told reporters on Tuesday.
"Jonathan Woodgate picked up a knock on his knee which, again, we are assessing daily ... We're keeping them with us and hopefully they'll be right."
McClaren said he planned to take both men to Israel, who England face on Saturday and then to Spain, where they face Andorra in Barcelona four days later. "We want them with us for next week," he said.
England are already missing their first-choice right back Gary Neville and both left backs, Ashley Cole and Wayne Bridge, for Saturday's game at Ramat Gan.
McClaren on Monday called up Gareth Barry, who can play at left back or left midfield, and has two utility defenders for either flank in Jamie Carragher and Phil Neville.
With England having slipped to third in Group E behind Russia and leaders Croatia, McClaren knows they need to deliver after a 0-0 draw at home to Macedonia and a 2-0 defeat in Croatia in October.
Looking ahead to Saturday, McClaren said: "In any away game and especially in Europe and in internationals, you have to quieten the crowd, you have to control the game and play at your tempo.
"It's going to be a day for a backs-against-the-wall, character performance that we so often produce when we have to.
"And we have to do it this time in a hostile atmosphere, against a very good team who will be very, very up for this game."