In my opinion, Shehzad will perform much better in the company of Sharjeel as compared to the Jamshed of recent times.
Indeed, from what I have seen, Sharjeel is extremly similar to technically deficient batsmen like Sehwag in that he will not play long innings, unless in favouring conditions against certain bowlers, but he will more often than not give a start of 20-30 at 100+ SR. This would be an object of worry, especially when compared to the qualities of Jamshed, but that quickfire start, no matter how unpleasing or sloggish, could actually be a blessing in disguise.