Both players have mostly played in the AHL their entire careers, with a few NHL games for experience. A few years ago, Gleason played in four games for the Dallas Stars and was fortunate enough to record his first point of the season with an assist. Since then, he has not participated in league play. Attard, on the other hand, has made 29 NHL appearances so far, scoring two goals and six points while getting called up a few times. Last season, he played in 12 games for the Flyers.
This trade was probably made just to put both players in better positions. Since neither player was expected to play this season, it probably won't have a significant effect on either NHL team. Both have spent the entire year in the AHL thus far. However, you never know what might happen, particularly following a trade, so keep an eye on both players as they might soon make their season debuts with their new teams.