Jalal limped off 59 minutes into Cherries' 1-0 win over Shrewsbury on Saturday, with rookie goalkeeper Dan Thomas replacing the former Peterborough man.
The injury was a second setback in as many weeks for Jalal, with the 26-year-old missing Cherries' 2-1 FA Cup defeat against Notts County after twisting an ankle in training.
And with the trip to Lancashire looming, boss Howe faces an anxious 24 hours before the full extent of Jalal's injury is known.
Cherries physio Steve Hard told the Echo: Jal injured his right Soleus, which is the muscle below his calf. It's better than what it was after the game, but he was due to have a scan either last night or this morning. I'll have the results tomorrow morning.
He's a doubt for Saturday, but we'll know more in the next few days.
Midfielder Anton Robinson, meanwhile, was replaced after just 14 minutes on Saturday after complaining of back pain, but could return to training on Thursday.
Hard added: With Anton it was stiffness in his lower back. When the game started it just seized right up. He's much better and should train later this week, so we're hopeful for him for Saturday.
Robinson said last night: I saw Steve yesterday and this morning. We're doing a lot of treatment on it and it's a lot better than Saturday. I've got an appointment with the chiropractor so we'll monitor it and hopefully I'll be back training on Thursday.
But there's been a big improvement since Saturday so I'll keep up with the rehab and see how it goes.