Showalter was at U.S. Cellular Field on Sunday morning, but was taken to the hospital about two hours before the game. He was accompanied by trainer Jamie Reed and met there by Daniels.
"He was handling it really well," Daniels said. "He was alert and on top of it. He was very calm, but I think the calmness was handed down from the doctors."
Dugout coach Don Wakamatsu served as manager in a 5-0 loss to the Chicago White Sox.
Showalter had only missed one game in 3 1/2 years as the Rangers manager prior to Sunday. He missed a game in Minnesota on May 15 last year so he could attend his daughter Allie's high school graduation in Florida.
The Rangers still have a number of unanswered questions about their starting rotation for next week.
Adam Eaton pitches on Tuesday, but the Rangers still haven't decided who he will replace in the rotation. It will either be left-hander John Rheinecker or right-hander John Wasdin.
It appears the Rangers are leaning toward keeping Wasdin in the rotation and will pitch him on Wednesday against the Yankees. That the Yankees are 20-9 when the opposition starts a left-hander is only part of the equation.
Rheinecker can be optioned to Triple-A Oklahoma, and the Rangers want the pitcher who gets bumped from the rotation to keep pitching every fifth day for the RedHawks. That would keep him as an option if there is a need in the rotation. Wasdin would have to first clear waivers before he can be sent down.
The Rangers also have to decide when John Koronka will pitch again. His turn comes up on Friday against the Kansas City Royals, but the Rangers' off-day on Thursday means they will likely push him back at least two days.
That would allow Vicente Padilla and Kevin Millwood to start on Friday and Saturday on their normal rest.
Loe has rough start:
Kameron Loe's third start on medical rehabilitation assignment did not go as well as the Rangers had hoped on Saturday night, and he's not ready to be activated from the disabled list.
Loe, sidelined with an elbow injury, allowed four runs in 2 1/3 innings for Oklahoma in a 6-1 loss to Nashville. He gave up four hits and five walks while striking out two.
Pitching coach Mark Connor talked with Oklahoma pitching coach Andy Hawkins about it Sunday morning, and the plan is for Loe to make another start on Thursday for Double-A Frisco.
"He just struggled last night," Connor said. "No command. He couldn't get his breaking ball or his changeup over the plate, and he was missing with his fastball. He felt as if he had a dead arm, which is understandable.
"Like I said to Hawk, it might just be a clunker. Everybody has one. Five walks is very unlike Kam."
Cordero leads in wins:
Francisco Cordero was the winning pitcher in Saturday's game, earning his seventh victory of the season. That's the most by any reliever in the American League, one more than Minnesota's Joe Nathan. Cordero has allowed just two runs in his last 15 appearances for a 1.20 ERA.
Cordero, going into Sunday's game, was tied with Scott Proctor and Kyle Farnsworth of the New York Yankees with 48 appearances, the most in the American League.
Michael Young, after Saturday night's game-winning hit, is batting .429 with two outs and runners in scoring position, the highest in the AL. But Young is 8-for-11 when the runner represents the tying or winning run, the highest in the Majors, in a minimum of 10 at-bats. ... The Rangers scored 32 runs in their first five games at U.S. Cellular Field and 20 scored with two outs. ... Mark Teixeira bobblehead dolls will be given out to the first 20,000 fans before Saturday's game with the Kansas City Royals. ... Spector's Gun Collection will perform an oldies concert following Friday's game at The Patio, located on the north lawn between Ameriquest and Mark Holtz Lake.
Kevin Millwood pitches at 6:05 p.m. Monday against the New York Yankees at Ameriquest Field in Arlington. Randy Johnson pitches for the Yankees.
The game has been moved up an hour so it can be shown nationally on ESPN. It can be seen in the Dallas-Fort Worth area on kdfi/Ch. 27.
The first 8,000 children, 13 and under, will receive 2006 Texas Rangers baseball cards.