Jenkinson needs to learn or risk falling down the leagues

Another game gone a decent point against stoke and another clean sheet with Tomkins at right back. Now while Tomkins wont offer you much going forward, he can defend which in my opinion is more important. Think I saw a stat saying we haven't conceded a goal this season while Tomkins is at right back. Now like Cresswell, Jenks loves to get forward now I see many people saying Jenks has just hit a bad run of form. What I cannot understand is how someone who has been given so many chances this season still makes the same mistakes every time he plays. The amount of goals that have been directly at the fault by Jenkinson this season almost hits double figures if it hasn't already. This all started from the Leicester and Bournemouth games where both our full backs has a torrid time. Now what irritates me most is since then you have two ends of the scale from both our full backs. You have Jenkinson who refuses to learn and Cresswell who in my opinion is getting better and better with every game and looks like Bilic has been working on his defensive side. So why can't Jenkinson also learn? Can he not learn? Or do you think Bilic isn't as interested in teaching jenks the basics. Tomkins at right back on saturday was a big statement by Bilic with reid injured. Is Jenkinsons time done at the club? One things for sure he needs to stop making the same mistakes otherwise his career will be short lived at this level.