It's huge. If he's the same player he was before he was hurt, that's just as important as whoever hits behind Barry. If Ray's on base ahead of Barry, that's more likely to force teams to pitch to Barry.
Every successful team has true baseball players with the makeup, drive and desire of Bill Mueller. His ability to hit from both sides of the plate will give (manager Grady Little) additional maneuverability.
There's a lot of things you want and one is competition. Teams that are set don't have people pushing for playing time. I believe in competition.