Morgan doesn't catch many of the passes thorwn his way. That's the bottom line. Yes, sometimes QBs throw the ball away in the direction of a WR, but Morgan has a much lower catch percentage than the other WRs he played with last year, so either the QBs just happened to throw the ball away in his direction a lot or he just doesn't catch the freaking ball. While AB had more drops than Morgan, he caught a lot more of the passes thrown his way.
Morgan only caught 45.6% of the passes thrown his way - 42.9% with the Browns and 46.8% here. He was the target on 68 plays and only had 31 catches.
Bryant caught 58.6% of the passes thrown his way - 59.3% here and 58.3% with the Browns. He was the target on 99 plays and had 58 catches.
So Bryant dropped more passes than Morgan, but also came down with the ball a higher percentage of the time. Project Morgan's stats out to the same number of attempts as AB and he would still have 13 less catches - at an average of 14 yards per catch that's a difference of 182 yards for the same number of pass attempts to the receiver. So whether QM drops the ball or doesn't make the effort to catch it or whatever, he doesn't get the it done at his primary job - receiving.
And for the record Terry Glenn caught 64.9% of the passes thrown his way, Key caught 56.5% and Witten caught 71.3% of his. So Morgan was either the only guy they 'threw the ball away' to or he simply sucks as a WR.