Cunningham separated his shoulder in last week's 20-17 win over Capital and it's unsure whether he will need surgery for the injury.
That win last week was also significant because Grier took over for incumbent quarterback Jon Alexander and led SC on two fourth-quarter touchdown drives.
"There are two things that really dictated him [Grier] starting more than his performance last week," Messinger said. "The first being A.D. getting hurt. It really hurt us on the defensive side of the football. People don't realize that Jon Alexander has wanted to play defense here for the last two years but we wouldn't let him. The fact that A.D. is gone dictated the start for Kentre as Jon not getting it done last week. Jon is there if we need him and he knows that."
After a 14-all halftime tie, SC opened up the lead in the second half.
Ray-sheed Coleman returned an interception 24 yards for a touchdown on just the third play of the half, Grier added his second touchdown run on a15-yard scamper and Coleman scored on a 4-yard run.
Three of SC's next four games are against sub-.500 teams (Nitro, Lincoln County and Ripley). It ends the season at Parkersburg, a team which ended SC's playoff hopes with a 29-13 loss.
"We are in pretty good shape right now," Messinger said. "There are still people left on our schedule that can trip us up. We just have to stay focused and play football and get out there and win football games."
Last year, SC started 1-4 before winning four straight then finishing 5-5.
Kirby led SA with 132 rushing yards and a touchdown.