I noted in February that, during a stretch of games from Jan. 29th through Feb. 4th, Ivan Johnson averaged 23.5 minutes, 9.5 points and just under 8 rebounds per game. Ivan's minutes have been up and down ever since, but he is currently on another productive stretch where he's averaged over 20 minutes per game.
In the last 4 games, Ivan has averaged 22.5 minutes, 11 points and 5 rebounds. The 8 games previous to that, Ivan averaged 14.75 minutes, 5 points and 3.5 rebounds.
For the season, Ivan has 27 games in which he has played at least 15 minutes. In those games, Ivan has averaged 21.7 minutes, 8.6 points and 5.3 rebounds. By contrast, in the 10 games since March 23rd that Marvin Williams has come off the bench, Marvin has averaged 27.9 minutes, 12 points and 5 rebounds.
If you project Ivan's production on a per-minute basis, you can see that, given the same minutes as Marvin, he could be expected to produce nearly as many points and more rebounds. That's not to denigrate what Marvin is producing off the bench. What's remarkable is the rate at which Ivan, an undrafted rookie, is producing relative to the former #2 overall draft pick.