By Michael Vega, Globe Staff

Sporting a black walking boot on his right foot, color-matched his left street shoe, Red Sox designated hitter David Ortiz strolled into the clubhouse before Thursday night's game against the Chicago White Sox and expressed his frustration over having to go on the 15-day disabled list with a strained right Achilles' tendon.

"Of course I want to be on the field, like usual,'' Ortiz said. "But those things I can't really control. That's part of it. I'm a little frustrated, I'm not going to lie to you, especially with having some guys coming back and the way things are going.''

Ortiz suffered the injury rounding second base on Adrian Gonzalez's three-run homer in the eighth inning of Monday night's 5-1 victory over the White Sox, awkwardly stepping on the bag.

He underwent an MRI exam Tuesday in Boston, then flew to Miami Wednesday to seek a second opinion from Dr. Harlan Selesnick, the Miami Heat's team physician, who concurred with the first opinion: Ortiz had a strained right Achilles'.

"They said pretty much the same thing, just to sit out and just wait a couple of weeks, get it treated and it'll be fine,'' Ortiz said.

Asked why he went to Miami to seek a second opinion, Ortiz explained one of his agents, Diego Bentz, of Fort Lauderdale, Fla., was friendly with Nick Arison, son of Miami Heat owner Micky Arison, and that they offered up Selesnick's services for the second opinion.

"Basketball players deal with that [injury] often and this guy was one of the best at it,'' Ortiz said. "When I went down there, the doctor there [Selesnick] totally agreed with what the doctor told me here, so everybody's on the same page.''

Asked how he felt about the way the team responded in his first day on the DL, erupting for 10 runs and 14 hits, including three homers combined by Cody Ross and Adrian Gonzalez, Ortiz brightened, saying, "That was great, man. To me, that's the best thing that can happen to somebody like myself when you go on the DL. You keep on watching the guys holding on and providing wins, so at least you don't feel that guilty.

"Like I said, I'll continue getting treatment and be back in a couple of weeks and hopefully everything goes well and I'll be on a pace the doctors are expecting me to be.''