One of Toilolo's biggest weaknesses is his separation skills—he simply can't pull away from average players in coverage.
His speed is decent (4.86 40 time per NFL.com), but he's not explosive off the line and lacks burst.
On this first play, the interception isn't Toilolo's fault—the pass was telegraphed and the decision was bad—but you can see that he can't get separation from the linebacker up the seams. That's a deep-threat TE's bread and butter, and he can't pull it off.
The next play displays the same issue. He can't shake the LB up the hashmark, forcing him to try to make a play on his knees.
Toilolo needs to develop consistent separation skills, which includes improving his explosiveness off the snap and short-area quickness. Until he is able to take advantage of mismatches against LBs, he won't be a viable receiving threat in the NFL.