IRVING, Texas -- While he still needs to be cleared to play in Wednesday’s regular-season opener at the New York Giants, Cowboys tight end Jason Witten will practice Saturday for the first time since suffering a lacerated spleen against Oakland on Aug. 13, according to a source.

Cornerback Mike Jenkins will make his on-field debut after missing the offseason and training camp while recovering from right shoulder surgery. However, like Witten, Jenkins will be limited in what he will do in practice.

Nose tackle Jay Ratliff, who took part in Thursday’s walkthrough, will not practice because of a high left ankle sprain suffered Aug. 25 vs. St. Louis.

A scan of Witten’s spleen Aug. 28 revealed the injury was healing but he was not cleared by the specialist for contact. The Cowboys will be in pads, but Witten will likely be kept out of the running game portion of practice. In the last week, he has increased his on-field activity with resistance training, running routes and catching passes after being forced to be “idle” for a week following the hit from Raiders linebacker Rolando McClain.

On his weekly show on KRLD-FM Friday, owner and general manager Jerry Jones said the team is measuring the benefit of keeping Witten out of the Giants’ game with an 11-day break before the Week 2 game at Seattle.

Witten has missed one game in his career because of a broken jaw in 2003 and has played through numerous other injuries from a broken rib to sprained knees.

If Witten cannot play, then the Cowboys would start John Phillips and have rookie James Hanna as the backup.

Jenkins was cleared from the physically unable to perform list on Wednesday after passing his physical but the likelihood of him being ready to play against the Giants after an eight-month layoff is remote at best. The Cowboys are prepared to go with Brandon Carr, Morris Claiborne and Orlando Scandrick as their top three cornerbacks vs. the Giants and hope Jenkins will be able to play against Seattle.