We had a similar problem like you at our soccer field. We had 3 types of common throughout the field so what we did was while installing a irrigation system we cut up the middle of the field which sees the most damage and put in 10 tons of beach sand...which is cheap here but probably not so much up there and then sprigged with TifSport. Not sure if it can grow up there but we are looking at switching to Celebration Bermuda grass to replace the outside and eventually the whole field because we play winter soccer and Celebration allows us to play the entire season (into February) without having to reseed the field. We've got about a 20 yard patch we are testing and going to see if we like it more than the 419 or Tifsport. Let me know what y'all come up with.
I would try to get a reel mower if at all possible because with TifSport if you cut it with a rotary no matter what height it looks bad but we cut it at 1 inch with a reel and it looks beautiful.