Because Pep saw him as a hybrid CB/LB, as LB has been a nightmare for Citeh until they got Cancelo, who is a bit like a poor man's Maldini (a right footer who is superb as a LB, although Maldini was far more ambipedal than Cancelo, and a far better player overall, the best combo defensive back (as he also was a top 10 all-time CB) in football history, and for me the 2nd best defensive back ever, after Franz Beckenbauer, and that call is a close run thing)