West Brom targeted Funes Mori a lot in our last meeting so Jagielka might be a response to that.
Not that Jags is strong enough or big enough to handle Rondon in the air (he isn't) but he's an upgrade in terms of positioning and should do a better job of keeping Rondon in front of him. Funes Mori isn't particularly good at staying goal side of his man on long diagonals and West Brom obviously love that pass.
Edit: Should have checked West Brom's line-up. No Rondon!