By the way, the answer to my question earlier... here's a sample of some roster moves for free agents this past february:
2/16: Pirates signed Tyler Anderson. Placed Jose Soriano on the 60-day IL
2/16: Marlins signed Adam Duvall. Placed Jeff Brigham on the 60-day IL
2/16: Giants signed Jake McGee. Placed John Brebbia on the 60-day IL
2/16: Rays signed Rich Hill. Placed Colin Poche on the 60-day IL
2/17: Padres signed Mark Melancon. Placed Trey Wingenter on the 60-day IL
2/17: Mariners signed James Paxton. Placed Andres Munoz on the 60-day IL
2/17: Padres signed Keone Kela. Placed Mike Clevinger on the 60-day IL
2/18: Dodgers signed Justin Turner. Placed Caleb Ferguson on the 60-day IL
2/19: Mets signed Taijuan Walker. Placed Noah Syndergaard on the 60-day IL
2/22: Yankees signed Brett Gardner. Placed Luis Severino on the 60-day IL
2/22: Rays signed Chaz Roe. Placed Yonny Chirinos on the 60-day IL.
2/22: Rays signed Collin McHugh. Placed Oliver Drake on the 60-day IL.
When spring training starts, teams can stash players on the 60-day IL. They have extra roster space. In this era of extending the roster and shuttling players back and forth, teams are maximizing their 40 man roster.
Back-end borderline 40 man roster guys don't really have much offseason value when 40-man roster spots are so precious that teams wait until February to make their free agent moves.
That is why if the Tigers trade for somebody like DeJong, it will likely be a reliever or two a ways off.