Ipswich Town defender Ibrahima Sonko is rated doubtful for this weekend's trip to Middlesbrough after stretching a knee ligament.
The 30-year-old lasted 35 minutes of Tuesday's 3-0 win over Coventry.
"It's going to be tight, we can't seem to get any training into him," Jewell told BBC Radio Suffolk.
"He's stretched his knee ligament, which is really unfortunate, we'll give him as much opportunity to recover but time's probably against us."
Jewell has the option of turning to Damien Delaney or Ivar Ingimarsson to partner Danny Collins at centre-half at the Riverside.
And winger Lee Martin could be considered, following his three-match suspension and dressing down by Jewell in August, but will need to overcome illness.
The Town boss said: "I had forgotten all about him to be honest, it's been so long since he's been able to play for us.
"He's had tonsillitis this week. He's trained well while he's been suspended, in fairness, and if any player is available they'll be considered."
But left-back Mark Kennedy has suffered a setback in his return from a calf injury.
"He tried to come back training and nicked his calf a little bit, he's going to have to take a bit of time," Jewell explained.
Meanwhile, the former Wigan manager expects to make a decision on the future of young striker Caolan Lavery soon.
The 19-year-old Northern Ireland Under-21 international, who is currently on an academy deal, scored twice in a 5-0 reserve match against Peterborough in midweek.
"We gave him until October to prove himself because of his injuries last season," said Jewell.
"Certainly over the last month or so he's really come on.
"He's one I'm going to have to make a decision on very soon."