Crawley Town trio Dannie Bulman, Lewis Young and Thomas Verheydt are all being assessed after picking up injuries.
All three came off the field during Reds’ 2-0 defeat by Charlton Athletic in the Checkatrade Trophy on Tuesday night.
The Addicks, managed by former MK Dons boss Karl Robinson, played a young team with an average age of 22 which included ten players from their own academy and won the game through goals by Ben Reeves on 37 minutes and in the 69th minute by substitute George Lapsie.
Kewell said: “Obviously running down the wings, I put a lot of pressure on my full-backs - a lot of hard work and Youngy’s (Lewis Young) just felt a bit tight.
“Dannie’s (Bulman) played every single minute of the games, no-one’s indestructible unfortunately; he felt a litle twinge around his back so we will assess that.
“Thomas (Verheydt) took a knock to his knee, again he will be assessed and I will have to wait until I get the information.”
Understandly coming after their first win of the season 3-0 away at Swindon, Kewell was disappointed with the result.
He said: “I felt we did enough to get something out of it.
“Unfortunately the two goals came from our mistakes, so that’s something we have to really look at.
“We had a right go at them in the second half. We put pressure on them but we didn’t get the critical finish. We just need to get the ball in the back of the net. I can’t fault them.
“I felt there were a few players who haven’t had minutes and I felt they did really well, Kaby (Djalo) especially.
“There’s just a few little cracks here and there which we’re filling in and we’re going to make sure they’re done properly.
“We are not going to put a band aid over it, we’re going to make sure that players know each other and every role and when they do they are going to click together.”