Nelson is dominating with the Triple-A Nashville Sounds. He is 7-1 with a 1.51 ERA and a WHIP of 0.89. In 77 2/3 innings over 12 appearances, 11 of them starts, he has given up just 46 hits, walked only 23, while striking out 86.
Plus, Nelson pitched well in a brief September callup last season, and then repeated the success last month. Called up to make a spot start in place of Yovani Gallardo, Nelson pitched 5 2/3 shutout innings and picked up the victory. He is, by any reasonable definition of the term, ready.
Estrada, meanwhile, is ready to give up another home run. On Sunday against the Reds, he gave up three home runs in five innings. He gave up two home runs in the first inning, giving the Reds a 3-0 lead. The Brewers battled back to tie the Reds in the fourth. But, presto, in the top of the fifth, Estrada gave up a two-run homer to Todd Frazier. The Brewers eventually lost, 13-4, after a bullpen meltdown, but the five runs Estrada gave up were all the Reds needed.
Unfortunately for the Brewers, Estrada giving up home runs has been a truly routine development this season. He has allowed 23 home runs in 84 innings. Coming into Sunday, no other Major League pitcher had allowed more than 16.
At this pace, if Estrada were allowed to remain in the rotation and take his regular turn throughout the season, he would challenge the single-season record for home runs allowed, which is 50. The franchise record for home runs allowed in a single season, 39, is entirely too close for comfort.
Estrada has been a capable, if somewhat injury-prone Major League pitcher over portions of four seasons. Leg injuries limited him in each of the last two years.
But the 23 home runs in 84 innings represent a level of work that doesn't rise to the level of "capable." At this point, Estrada is a fly-ball pitcher in a hitter-friendly park who isn't getting it done.
Estrada has not had a truly effective start since May 13. In the six starts since then, he has an ERA of 7.01. Not at all coincidentally, he has given up 13 home runs in those six starts.
The Brewers, to their credit, have spent the last 71 days in first place in the NL Central. Widely picked to finish third or, more predominantly, fourth, in this division, they have been much better than that largely on the strength of pitching that has been much better than that.
If they are serious about maintaining that status, they cannot have one-fifth of their rotation serving primarily as a boost for the opposition's slugging percentage.
After Sunday's performance, Brewers manager Ron Roenicke was asked about Estrada's status in the rotation.
"We'll stay with it, talk about it and see if we can get it straightened out," Roenicke said. "Right now, I haven't had that discussion with [general manager] Doug [Melvin].
What factor would argue against making the change to Nelson?
"Next start's in Colorado," Roenicke replied.
Roenicke acknowledges Estrada's recent struggles, but he appears to remain in Estrada's corner.
"He's not pitching well right now," Roenicke said. "He's making mistakes and they're not missing them…. He's leaving some off-speed [pitches] up. When he's good, his breaking ball and his changeup those two pitches are down.
"Some guys you stay with because of the history. I think Marco falls into that [category]. He's done a nice job for us. He's going through a spell and hopefully he gets out of that and gets back to that really good pitcher.
"He's good when he's on. You guys [reporters] have seen him on. I've seen him on. He can go through good lineups when he's on. We have to figure out how to get him back to that."
Estrada wisely declined to get into any speculation about his job security. Coming into Sunday's game he said, "I felt great" both mentally and physically, but surrendering the two home runs in the first inning, "I was trying too hard; way too hard."
After that, he put up three scoreless innings before the two-run homer in the fifth. Overall, Estrada said of his outing, "It was a step in the right direction. I know that sounds bad after what happened, but it was."
Estrada has been a respected member of successful teams in Milwaukee. Nobody disputes that. But right now, he is not contributing to the success of what has become, surprisingly or not, a genuine contender. This appears to be a time not for infinite patience, but for decisive change.