ARLINGTON -- Josh Hamilton took batting practice on Friday wearing contact lenses. The new lenses gave a red tint to his eyes, and Hamilton is hoping they will help reduce the brightness that causes him some problems during day games.

"I have never worn contact lenses in my life, but I would like to be able to see the ball in the daylight," Hamilton said. "I'm trying every means possible, because I care and I want to be out there and I don't want to stink during the day."

Hamilton went into Friday night's game against the Mets hitting .376 with a .415 on-base percentage and a .661 slugging percentage at night. He was hitting .122 with a .246 on-base percentage and a .184 slugging percentage during day games.

Last year, during his MVP season, he hit .384 with a .688 slugging percentage at night and .286 with a .474 slugging percentage during the day.

"I talked to the medical staff and told them to figure out something that would help me," Hamilton said.

The Rangers have day games on both Saturday and Sunday against the Mets. Hamilton is expected to start in both games. He said after batting practice Friday that the contact lenses do seem to help, and he will try them on Saturday.

Daniels scouting pitcher Darvish in Japan

ARLINGTON -- Rangers general manager Jon Daniels has left the country. He is spending time scouting in Japan, and one of the pitchers he is watching is Yu Darvish.

Darvish is a right-hander who can be a free agent and jump to the United States this winter. The Rangers, who were aggressive in their pursuit of Daisuke Matsuzaka in 2006, are expected to be one of the teams interested in Darvish.

Rangers pitcher Colby Lewis faced Darvish during his two years in Japan, and said he thought Darvish can make the jump to the United States.

"He's got great stuff and he keeps the ball in the zone," Lewis said. "When I saw him he was 93-95 [mph], he had four pitches, and he was throwing them for strikes. Successful guys are the ones that do that. He doesn't walk many guys, and he has strikeout stuff."

Darvish, who turns 25 in August, is currently 8-2 with a 1.39 ERA in 10 starts for the Hokkaido Nippon Ham Fighters. Coming into the season, he had a career record of 58-22 with a 1.81 ERA in 98 starts and two relief appearances over four seasons. He had 40 complete games while averaging 6.1 hits, 2.1 walks and 9.2 strikeouts per nine innings.

"Anybody who can throw all their pitches for strikes can pitch in the big leagues," Lewis said. "That's what it takes."

The Rangers have grown to be one of the most aggressive teams in the international free agent market, and they signed reliever Yoshinori Tateyama this offseason. He spent 12 seasons with the Fighters, including four as a teammate of Darvish.

Napoli hoping for rehab stint next week

ARLINGTON -- Mike Napoli, who is sidelined with a strained left oblique muscle in his rib cage, began swinging with a regular bat on Friday. He took swings off a tee and against soft-toss pitching. He is hoping to take full batting practice by Sunday and go out on a medical rehabilitation assignment early next week.

"I feel good," said Napoli, who has been sidelined for two weeks and is eligible to come off the disabled list on Tuesday. "I don't feel it at all."

Rangers manager Ron Washington said he would like to see Napoli get at least 20 at-bats in the Minors before he is ready to return. He also wants to make sure Napoli is ready to catch nine innings before he is activated off the disabled list.

Rangers pitchers have a 2.73 ERA when Napoli is behind the plate. That's the lowest ERA for any catcher with at least 20 games caught in the American League.

Ogando prepared for the heat

ARLINGTON -- Rangers pitcher Alexi Ogando is from the tropical Dominican Republic, and he has spent a year pitching in Texas. He understands pitching in the heat. He just wasn't prepared for the humidity last Sunday in Atlanta.

"Atlanta was more humid, believe me," Ogando said. "I just didn't drink enough liquids."

Ogando will pitch on Saturday afternoon against the Mets, and it will be his first start since getting dehydrated during his five-inning, 105-pitch outing against the Braves.

"I'll be ready," Ogando said. "You never know what's going to happen to me on the mound, but what happened to me in Atlanta is not going to happen tomorrow."

Catcher Yorvit Torrealba also got dehydrated on Sunday in Atlanta. He will be behind the plate on Saturday, but manager Ron Washington said Taylor Teagarden will catch on Sunday.

Worth noting

• The Rangers are promoting Class A All-Star pitcher Joe Wieland to Double-A Frisco. He will start on Monday night.

• Pitcher Eric Hurley, who was on medical rehabilitation assignment, was activated off the disabled list on Friday and optioned to Triple-A Round Rock. It's essentially a paperwork move. Hurley had been sidelined for two months with a concussion after getting hit by a line drive, and the Rangers had put him on the 60-day disabled list to make room on their 40-man roster. They are back to having a full 40-man roster.

• Ian Kinsler, after a stolen base on Wednesday night, went into the Mets series with 121 career stolen bases in 141 attempts. That is a success rate of 85.8 percent, the second-best percentage among active players with at least 120 attempts. Carlos Beltran has the highest at 88.2 percent.

• Outfielder Leonys Martin (back) has begun a medical rehabilitation assignment with the Arizona Rookie League Rangers.