Two American League powerhouses will be without some of their top veterans to start the 2015 season.

The Detroit Tigers and Oakland Athletics have experienced fairly significant setbacks less than a week before Opening Day. Starting pitcher Justin Verlander and outfielder Coco Crisp will not be able to kick off the season on the 25-man roster.

Verlander will start the season on the disabled list because of tightness in his right triceps muscle, but manager Brad Ausmus is "optimistic" that the right-hander will be able to make his regular season debut against the Cleveland Indians on April 12, according to George Sipple of the Detroit Free Press.

This will be the first time in Verlander's 10-year career that he'll be placed on the DL. Six days ago the 32-year-old was forced to leave his start because of the injury and he has yet to return to action. Verlander told Jason Beck of MLB.com that his "whole body just kind of feels tight" because of the mechanical adjustments he has made.

Verlander and Ausmus have insisted the injury isn't serious, but it's clearly affecting his ability to play. Texas Rangers starting pitcher Yu Darvish experienced some tightness in his triceps early in March and an MRI revealed a partially torn UCL. He was forced to undergo Tommy John surgery and will miss the entire 2015 season, which is something to potentially keep in mind with Verlander.

Speaking of surgery, Oakland Athletics outfielder Coco Crisp will also be out of action to start the year. His right elbow has been bothering him during spring training and the issue has become clear.

"The Chronicle has learned that Coco Crisp is expected to need surgery to remove a bone spur and chips in his right elbow, and he would miss six to eight weeks after the arthroscopic procedure," according to Susan Slusser of the San Francisco Chronicle.

This is the third significant injury the A's must deal with this spring. Outfielder Josh Reddick will miss at least the first five games with an oblique strain and closer Sean Doolittle is expected to miss at least the first month of 2015 because of a slight tear in his rotator cuff.

As a result, the team may have to shake up their roster and move Ben Zobrist to the outfielder and put Eric Sogard at second base, which FOX Sports' Ken Rosenthal suggested on Thursday. Depending on how Sam Fuld and Craig Gentry perform while Reddick and Crisp are sidelined, general manager Billy Beane could still strike a deal for another outfielder.

While Doolittle is down, Tyler Clippard will assume the closer role.

Opening Day is Apr. 6, so we'll soon see how these clubs adjust to these injuries.