The Red Sox have signed 38 year old Carlos Delgado to a minor league contract. Obviously there is no reason to rush out and grab him at this stage. He is headed to the minors and could be there as long as a month as his contract requires the Red Sox call him up or release him by September 1.
There are two aspects to note in your fantasy leagues. If you picked up Mike Lowell expecting full time at bats you can expect those to end soon. On the other hand even if they call up Delgado he is recovering from his own hip problems and likely won't be headed to full time work.
The addition seems to be more of an insurance policy than anything. He is a more patient hitter and also had more power, but we'll need to see what he does in the minors to see if he still has the ability to SLG greater than .500 like he did before the injuries.
Recommendation: Lowell owners using him as an injury fill in should continue to use him for now. He might share a few days with Victor Martinez, but for now should get a large amount on work. If Delgado gets called to the majors its probably best just to avoid the whole situation. I would think Delgado sees the most work, but not enough to be played in most leagues.