Well, the Phillies essentially ran a three-man bench (and a seven-man bullpen to boot) for all of August, so if they still value Pache it's theoretically possible to keep him. He'd be very lightly used. Maybe starts in LF against tough lefties when Merrifield also plays 2B. Defensive replacement for Merrifield when he starts in LF. He'd essentially be a Rule 5 player (due to his lack of options).
But, it would be best for Pache to go join a bad team or a team with less OF depth and get more playing time. It would also just be ideal if they can flip him for a similar player, but LH. Or flip Cave for a better bat even if he's a bad fielder.
I don't think Cave's lack of versatility is an issue though when they already have Sosa and Merrifield. Cave can also technically play CF (and so can Merrifield). If Darrick Hall could actually play passable LF I'd be more inclined to give him a shot, the fact that he is only 1B/DH when our starters are both LH is what hurt him there.
If you need more versatility than what Cave has you end up with Kody Clemens, because anyone who is that versatile and better than Cave or Clemens.... well, gets an $8 million free agent contract. Or more.