Kory Roberts was carried off on a stretcher as the Saddlers were beaten 3-0 by Stoke in a pre-season friendly.
Early goals from Bojan Krkic and Ibrahim Afellay, and a Peter Crouch effort, secured a comfortable win for the Championship side.
But the result was overshadowed by a serious-looking injury to Kory Roberts, who required oxygen being leaving the field.
In Gary Rowett’s first public match as Potters boss, the visitors made a lightning start with two goals inside the opening four minutes.
Bojan struck first, arrowing a 20-yard right-footed shot beyond Liam Roberts, before Afellay added a second with an unerring low drive from a similar distance.
With Joe Allen and Charlie Adam pulling the strings in midfield, Stoke enjoyed long periods of dominance and pushed the Saddlers back into their own half.
The hosts’ first sight of goal came from the trialist on 20 minutes, but his right-footed attempt was comfortable for Adam Federici.
Having recovered from that dreadful start, Walsall registered a couple more attempts before the end of the half.
A tame George Dobson effort bobbled harmlessly wide before Ismail fired powerfully over after a good run and pass from the trialist.
A low-key second half was punctuated by a third Stoke goal on the hour, Peter Crouch with a deft near-post flick from Erik Pieters’ accurate low cross.
The Saddlers produced a fine passing move with 13 minutes left.
Liam Kinsella played the ball down the left for Dylan Parker, who in turn found Candlin with his back to goal.
The young striker turned and crossed to the far post but Kieron Morris planted his header wide.
Walsall were dealt an injury blow in the closing stages as Kory Roberts collided with Ryan Sweeney and went down holding his leg.
The young defender received oxygen during a lengthy spell of treatment before being carried off on a stretcher.
Team first 60 mins (4-4-2): L Roberts; Devlin, K Roberts, Guthrie, Leahy; Ismail, Chambers, Dobson, Trialist; Cook, Bakayoko.
Team last 30 mins (4-4-2): L Roberts; Little, K Roberts (Peters 86’), Leivesley, Cockerill-Mollett; Morris, Kinsella, Sangha, Kouhyar; Parker, Candlin.
Attendance: 1,869 (970 Stoke fans).