Frozen arttificial turf would be like playing football on a rough-surfaced hockey rink. Worse that frozen turf. FAlling on ice bad - regardless where you do it.
Arizona had the right idea for their new stadium. Roll the grass outdoors into the sunlight during the week, roll it back indoors for games. Works. Too late for a retro-fit, now.
A proposal worth considering (or, pipedream from a fan 1,200 miles distant) is to have lightweight wheeled units of grow lights to supplement the filtered sunlight in SOFI. Topsoil, turf, and irrigation are easier problems to solve. Think: Big greenhouse.
Artificial sunlight for vogorous plant growth and dense, tough turf as an ideal playing surface, quick playing field recovery between games (given occasional two per week via sharing stadium with SD) would pay back many more dollars per dollar invested than the roughly million-dollars-per-game-per player loss due to players nursing lower leg injuries attributable to the playing surface.
