That is in contrast to the Iron, who will move back into the play-off positions if they pick up a point at Glanford Park.
"It will be a very tough game, even though they have only just been relegated they have known their fate for a number of weeks and have seen an upturn in form," he told the Iron's official website.
"They are a massive threat from set plays and launch it in from all over. They try to play as well, but they are massive from set plays as they launch it in."
United will be without their top scorer Gary Hooper, who has a dead leg, and the winger Martyn Woolford.
The midfielder Matty Sparrow is a doubt having missed training on Monday with a knock.
The Cheltenham manager Martin Allen is without six first-team players so includes several youth team members in his squad.
One player likely to start for the Robins is the former Iron left-back Lee Ridley, who Allen has singled out for praise for his performances in the final games of the season.