Colon, who returned to Cleveland on Thursday, joins relievers Zach McAllister (right hip) and Tommy Hunter (lower back) on the DL.
"He'll be non-throwing for about 3-4 days," Indians manager Terry Francona said of Colon. "Nothing structurally [wrong] or anything.
Due to a variety of issues throughout the season, Cleveland has cycled through 19 pitchers out of the bullpen. Closer Cody Allen, setup man Bryan Shaw and righties Dan Otero and Jeff Manship are the only pitchers who have remained in the Indians' bullpen since Opening Day.
As a group, Cleveland's 'pen entered Friday with a 3.72 ERA (seventh in the American League). As the Aug. 1 non-waiver Trade Deadline approaches, the Indians are in the market for help, and the club has been linked to Andrew Miller and Aroldis Chapman of the Yankees and Will Smith of the Brewers in recent trade rumors.
Lefty relief has been a consistent issue, and Cleveland will look to address that area before the Deadline.
On Friday, the Indians were close to signing veteran lefty Joe Thatcher to a Minor League contract, pending a physical. Thatcher, 34, was in camp with the Indians during Spring Training, but he was released on March 27. He signed with the Dodgers in April and appeared in 17 games at Triple-A Oklahoma City before being released again. Thatcher has a 3.38 ERA with a .232 opponents' average against left-handed batters in his nine-year career.
Colon, 26, was promoted from Triple-A Columbus on July 7 and has turned in a 2.45 ERA in three appearances (3 2/3 innings) for the Indians. In 13 games for Columbus, the right-hander had a 1.76 ERA with 14 strikeouts against eight walks in 15 1/3 innings.
The 25-year-old Anderson was scheduled to start on Thursday at Triple-A, but he did not pitch and has joined the big league club in Baltimore for the three-game weekend series. The big right-hander opened the year as Cleveland's No. 4 starter, but he was sent back to the Minors after some early-season struggles. Anderson has gone 1-4 with a 7.48 ERA in nine games (eight starts) with the Indians, but he has a 4.32 ERA in six Triple-A starts this year.
While moving Anderson to the bullpen helps a current need, it's "something we kind of thought about anyway," Francona said. "We want to see how it will work."
Jordan Bastian has covered the Indians for MLB.com since 2011, and previously covered the Blue Jays from 2006-10. Read his blog, Major League Bastian, follow him on Twitter @MLBastian and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.