I trained for Aussie Rules Footy, which is more speed endurance based than the football you're playing, but this is what I found worked.
Lift either on off days or before training, but make sure there is plenty of rest time between a lifting session and training.
Go submaximal loads. Don't work to failure and work within yourself so that you are still fresh, i.e. no DOMS. Best way is do eg; one rep with 2RM so that you tax your muscle to get stronger but not to the point of interferring with sport.
Remember that as the season goes on that you may have to settle for maintenance strength/size. Early in the season gains can be made but depending on how well you recover through the season will dictate when you have to accept little to no progress.
Everything else is pretty much as normal. This isn't a bulking phase, and you should be too active to pack on serious mass. With the extra activity you should lean out a bit so the eating goal is to maximise performance and maintain lean mass.
I was able to gain strength untill about halfway into the season then hit maintenance once injuries and recovery started hampering me. I actually gained weight (around 10lbs) but also leaned up a bit, though I really ate whatever I could, as running everyday, 3-4 weight sessions, two training session, and a game will chew through calories.