True, Fabinho isn't as fast as someone like Gomez, but he did an excellent job matching up to Werner's speed in the first half of their game against Chelsea. He might not be as strong as someone like Matip, but this ball distribution skills from defense would be very valuable. Right now, a midfield of Wijnaldum, and Henderson are better suited to the midfield shuttler roles and Thiago and Fabinho seem to be competing for the DM role. Moving him to their defense adds more composure and passing quality at the expense of speed, which doesn't seem like a bad trade-off.