No. A DFA is a step before waivers in order to remove someone from the 40-man roster.
Now that Leon has been placed on waivers, any team may claim him. If more than one team claims the player from waivers, the team with the weakest 2018 record in the AL gets preference. If no team in the AL claims him, the claiming team with the weakest 2018 record in the NL gets preference.
If Leon is claimed, the Red Sox may (1) arrange a trade with the claiming team within two business days of the claim; (2) rescind the request and keep Leon on its major league roster, effectively canceling the waiver; or (3) do nothing and allow the claiming team to assume Leon's existing contract. My guess is that, if claimed, the Red Sox will try to get a minor league asset from the claiming team and, if unsuccessful, will simply let Leon go to the claiming team.
If no team claims Leon off waivers after three business days, Leon may be assigned to the minors, traded (to any team), or released outright. In this case, Leon would likely be released outright; otherwise his entire salary becomes guaranteed on Thursday.