As mentioned in the post this could mean a lot of different things. Some athletes do this on a regular basis as a part of their routine. However, with all of the things that have happened between the two sides, there's likely more than just routine maintenance behind this.
With all of these rumors and problems between the two sides, a trade seems more likely by the day. To this point, Hart has been a good starter who has had bumps in the road while developing. He is still just 25 years old at this point with plenty of seasons left in front of him.