England international Jagielka, 33, picked up the injury in the 2-1 loss at Arsenal on Saturday and although Martinez was pleased his knee cartilage and cruciate ligament remain unaffected, the Spaniard could be without his centre-back for the next two months.
"I wouldn't expect anything longer than eight to nine weeks," Martinez said when asked about the defender's recovery timetable.
The injury will ensure England manager Roy Hodgson is unable to select Jagielka for the November friendlies with Spain and France while the defender's club side could be without their skipper for the remainder of the calendar year.
However, Martinez was upbeat about the severity of the problem amid initial concerns Jagielka could have been out for an even longer period of time following the challenge from his international colleague Alex Oxlade-Chamberlain.
"After the game we expected the worse, especially in the way that the injury happened and rotating that knee - it could have been anything," Martinez added.
"We had the scan and his medial ligament is affected, it's an injury that is quite straightforward from that point of view, but there is no other damage in the knee
The meniscus, the cartilage and the cruciates are very, very strong
It's the least (damage) that it could be."
Source : PA
Source: PA