Krystian Bielik has suffered a set back with the defender now ruled out for a few more weeks despite not yet having had the chance to play for his loan side.
Bielik joined Walsall at the end of the January transfer window however the 20-year-old was struggling to shake-off a hamstring problem after missing the first half of the season with a shoulder problem.
“Krystian has had a setback in his rehab,” said Jon Whitney, Walsall manager.
“Unfortunately he has tweaked his knee during late-stage rehab which has delayed the start of his loan spell with us.
“Krystian is due at the club in the next 10 days to meet with the squad and take part in some group sessions, and we look forward to Krystian joining the group in the next couple of weeks.”
Under contract with Arsenal until 2020, big things are expected of the u19 Poland centreback who impressed many with his loan spell at Birmingham last season.
Bielik signed for Arsenal from Legia Warsaw in the winter of 2015 for just over £2m.
He has managed just four Premier League 2 appearances this season, a total of 357 minutes. Two of those came in August with the remaining two coming in December.
Bielik is doing his rehab with Arsenal.