The Oilers announced via Twitter today:
Edmonton continues the search for any help in the middle, and Nashville's glut of centres made a nice match, but Roy isn't likely to be an impact player in the three months he'll be an Oiler. The Oilers could've claimed Roy on waivers, but Edmonton was already carrying 47 contracts and Roy's deal put them precariously close to the 50 man limit, though how that matters at this point in the season for this team is unclear.
Roy is 31 years old and on the downslope of his career, but could still produce given the right situation. He's not, however, a strong possession player at this point, nor is he particularly big or fast. But, the Oilers will get what they paid for, and Mark Arcobello wasn't any of those things either.
In some parallel universe, Anton Lander is all the rage, given how he replaced Boyd Gordon on the fourth line and allowed the Oilers some real flexibility up the middle for the first time in a very long time. In this universe, however, it's still the same old Oilers.