We could just hit the Laporte clause of 37M Pounds, toss him in at CB next to Smalling and let Blind compete with Rojo at LB.
Laporte doesn't leap off the screen as brilliant the way Varane or Marquinhos does but he's left-footed, calm, technically solid, good long passer (takes some free kicks even), has good size and has done very, very well for his age.
Certainly it would be a more long-term solution than panic signing an LB, and I think if used correctly Blind and Rojo could do a good job at LB until Shaw is back, with Rojo playing against scary, pacey wingers and Blind's passing getting him the nod when we are more worried about generating offense from that spot.
And next season, we'd have a balanced D:
Shaw-Laporte-Smalling-Darmian
Backed up by:
Rojo-Blind-Jones-Valencia
with McNair as the utility guy, on loan getting 35 Prem starts or as a backup CB if Rojo leaves in the summer, with Blind and Darmian (and Young) still strong backup LB options.
Only Valencia would be over 26.