"It seems like his strikeability, it's either really good or on the edge," Rangers manager Jeff Banister said. "Lately ... it's not typical of Diekman. He's normally a pretty decent strike-thrower, get ahead of hitters and put them away."
Diekman has a unique "cross-fire" delivery, but he can't get too "east-west." When he overdoes the cross-fire, that's when the command gets off.
"I feel the change I need to make is microscopic ... just something that I have to keep up," Diekman said. "It will be an easy fix."
Diekman still has impressive numbers, going into Saturday's game with a 2.85 ERA and a 1.01 WHIP. He is averaging 9.9 strikeouts and 5.5 hits allowed per nine innings.
Ailing Lucroy sits out
Rangers catcher Jonathan Lucroy was supposed to start on Saturday, but he was out of the lineup with flu-like symptoms. Robinson Chirinos started in his place, but Lucroy could return on Sunday.
"He came in ... he's good," Banister said of Lucroy. "There is no need to push it."
Lucroy has started 22 of 30 games since being acquired from the Brewers on Aug. 1. The Rangers have also added Brett Nicholas as one of their September callups to be their third catcher.
• Rougned Odor, who turned 22 on Feb. 3, has 28 home runs this season. He is trying to become the seventh player since 2000 to hit 30-plus home runs at the age of 22 or younger. The others are Bryce Harper, Manny Machado, Mike Trout, Giancarlo Stanton, Miguel Cabrera and Albert Pujols.
• The Rangers have had four players hit 30 home runs at age 22 or younger in club history: Jeff Burroughs (1973), Pete Incaviglia (1986), Ruben Sierra (1987) and Juan Gonzalez (1992).
• The Rangers' Dominican Summer League team opens a best-of-five series in the finals against the Red Sox's squad. It's the fourth straight year the Rangers have advanced to the DSL finals.
T.R. Sullivan has covered the Rangers since 1989, and for MLB.com since 2006. Follow him on Twitter @Sullivan_Ranger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.