The ship might not even have travelled by warp to the Delta Quadrant even if it had warp capability, it could quite easily have fallen through a wormhole. Alternatively a species such as the Nacene could have ‘wished’ the sleeper ship in to the Delta Quadrant, as Neelix might have said. Whether the Tellerite sleeper ship was warp capable or not is irrelevant, there are *many* possibilities as to how it found its way in to this area of the galaxy. Q may even have had a hand to play, but I can’t think of a reason why Q would be interested in a Tellarite sleeper ship. Until the Tellarite vessels logs are recovered, we may never know. I am also not sure if the technology exists even in the 24th century to power a warp drive for such an extended period of time, never mind in the 22nd century. I do not think that Tellarite warp technology was more advanced than the Federation in this era, but I could be wrong. Enterprise era warp drives were only capable of a maximum of warp 4.5 and that was from the latest model starships, I’m sure that the warp standard for most ships was probably around one half to two thirds this speed so the journey would have probably taken the sleeper ship far more than double the length of time that it would have taken the USS Voyager to traverse a similar distance at warp 9.975 in the late 2300’s. We also have to consider the various obstacles that would have been in the way of the sleeper ships journey to the Delta Quadrant. Just how far in to this quadrant did the Tellarite ship go? Did it have to traverse Borg Space at all? It is also possible that the sleeper ship could have accidentally followed in the wake of a Borg Cube and travelled through a transwarp conduit.