It's really not all that complicated when you think about it. Let me break it down for you.
Rondo was having his best season ever... averaging 13.7 points, 11 assists in 37 minutes. Pretty impressive. He's arguably responsible for 35.7 points. But his presence didn't leave a ton of minutes left for the other 4 guards on this team.
We can skip talking about Bradley, because Bradley's minutes aren't really effected. He just slides over the PG where he belongs (he's too small to play SG).
Leading up to the injury, Barbosa was getting like 5 minutes a night when he played... and getting DNP after DNP. In December, Barbosa averaged 1 point in 6 minutes per game... if he played at all.
Barbosa's last 4 games: 10.5 points 2.7 assists 23.25 minutes
Terry's last 4 games: 12.5 points, 4 assists in 28.25 minutes
Lee's last 4 games: 8.5 points, 3 assists in 30 minutes a night. About 7 minutes more than he usually plays.
Pierce is averaging 6.2 assists in the last 4 games.
Jeff Green is averaging 13.5 points in the last 4 games now that he gets to hold the basketball.
So basically you have guys like Barbosa (who would be getting DNP's) getting quality minutes. You got barbosa getting a couple assists, you got Terry getting a couple more assists, you got Lee getting a couple more assists and you got Pierce getting a couple more assists. Barbosa is scoring more buckets, Lee is scoring more buckets and Terry is scoring more buckets. At the end of the day, we have guys who are filling up the stats that Rondo usually gets. It's spread around more. The team is moving the ball more. Our best defensive guards are starting in the back court. We aren't starting a 6'2 180 pound player at SG. JEff Green gets to have a bigger role. The team doesn't have to worry about Rondo being a liability without the basketball. Losing Rondo hurts the team, but what we're gaining by him being out kinda evens it out. We'll continue being .500.
Welcome to the Freedom Offense.