His playing time was largely a victim of our absolutely terrible 3rd down conversion rate to start the season. The Packers offense was all feast or famine there for a while. And when they tried to use MVS as a weapon for conversion, he came up small.
In the first 9 weeks before MVS's snaps started dropping off the Packers were 39/107, 36.4% on 3rd. down conversions vs. 37.6% for the entire season. However, weeks 1 and 2 saw 8 of 30 conversions in a new offense against two good defensive teams. Weeks 3 - 9 saw a 40.3% conversion rate. None of these numbers are very good, hovering around the league average, with or without MVS.
In those first 9 weeks, MVS was thrown to 14 times on 3rd. down.
On short passes, as defined by pro-football-reference.com as 14 yards or less, MVS was 7 of 9 with 4 first downs, a 44.4% conversion rate, a respectable number, on par with Rodgers' 43.8% 3rd. down coversion rate on those throws.
On long passes defined as 15+ yards, it was 1 of 5 with one 1st. down. He was one completion shy of coming up to Rodgers 38% conversion rate on 15+ yard passes for the season.
All in all, he was one 15+ yard catch shy of the team average and respectability before being mostly benched even if as you say he didn't "come up big".
As it turned out Lazard, was very good on 3rd. down, for the season 13 of 19, 12 first downs, 63.2% coversion rate. It wasn't a case of MVS being a bad 3rd. down receiver as it was finding a more trustworthy option which more than anything distills down to better route running and competing at the ball, regardless of down.
At this point you'd pencil MVS in for a roster spot, but how deep in the depth chart is a whole other question. Who gets drafted and camp/preseason competition (if these things happen) could alter the picture.