I don't think so, he was only a desperation start before the injury and will be even more so now. Even before the injury, his usage was on pace to decline for the third or fourth week in a row. Williams and McKinnon will continue to get more usage even if CEH is healthy.
Week 1 - CEH had 17 touches for 72 empty yards, while playing 47 of the team's 65 snaps (72%).
Williams and McKinnon combined for 18 snaps (14 & 4), but only 1 touch
Week 2 - CEH had 13 touches for 46 empty yards (and a lost fumble), while playing 33 of the team's 51 snaps (65%).
Williams and McKinnon combined for 18 snaps (14 & 4), with 4 touches
Week 3 - CEH had 19 touches for 109 yards and a TD (and also a fumble), while playing 49 of the team's 79 snaps (62%).
Williams and McKinnon combined for 30 snaps (27 & 3), with 9 touches
Week 4 - CEH had 16 touches for 114 yards and a TD, while playing 35 of the team's 67 snaps (52%).
Williams and McKinnon combined for 32 snaps (24 & 8), with 12 touches
Before he got injured in week 5, he certainly was not a desperation start. Sure, his snap percentage was dropping, but he was RB19 even with the 2 weak fantasy games to start the season. He was an RB1 in both weeks 3 and 4.
CEH had 341 yards on 65 touches
Williams had 99 yards on 25 touches
McKinnon had 14 yards on 1 touch
A healthy CEH can be a very serviceable RB2, even if he cedes playing time. Now for the important question - how long before he comes back?