And Leighton Baines could be facing a spell on the sidelines after suffering concussion in the first-half at Selhurst Park.
The teenager was struck on the back of the head by the ball and had to be taken to hospital. League rules state that players who have been concussed should not play for two weeks as a precaution.
Manager Paul Jewell said: "It's a bit worrying with Leighton because he was slipping in and out of consciousness. He went to hospital with our kit man Joe Newton and the doctors kept him under observation.
"Leighton says he was hit on the back of the head by the ball and we'll have to see how he is. The rule used to be that players were out for two weeks if they were concussed."
Jewell knows already that he will definitely be without Roberts and Jarrett for matches next month. Roberts will miss the visit to Nottingham Forest on May 1 and the big clash with West Ham eight days later at the JJB.
While his sending-off was for two yellow cards which carries a one-match ban, he'll get an extra game punishment as it was his second dismissal of the season.
Midfielder Jarrett sits out the Forest game having seen red for two cautions.
Jewell didn't have too many complaints with the Jarrett sending-off but felt referee Mike Thorpe had buckled under pressure from the crowd to dismiss Roberts for a confrontation with Palace's Tony Popovic. And he was blazing too with the Ipswich official's decision to award a free-kick to Palace which led to their equalising goal.
Jewell said: "This referee was swayed by the crowd and I think he was a homer. I didn't see the linesman flag for anything leading up to when Jason Roberts got sent-off.
"But the reaction of the crowd made him think something had gone on. I'm told Jason was sent-off for adopting an aggressive attitude.
"As for their equaliser, the ref gave the free-kick for no reason in my opinion.
"I thought the referee was inept, although our performance wasn't too far behind."
Nathan Ellington's 19th goal of the season had given Latics the lead in first-half stoppage time.
And despite a below par display, they looked as though they were going to hold on until Danny Granville headed Palace level.
Jewell said: "I was disappointed with our performance really, we looked a bit sluggish and jaded. I think the best we deserved was a point, and we'd arguably have taken that before the game.
"It would have been nice to win it 1-0 because I couldn't see us scoring a second – until Nathan's goal I couldn't see us scoring one to be perfectly honest.
"We worked hard enough, but the quality wasn't there and we didn't seem to get out of second gear.
"Saying that, it's a point nearer where we want to be, and results rather than performances are what counts at the moment."
Source: Wigan Evening Post.
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