When the 2017 season begins in a few weeks, the Rangers will be without an important left-hander in their bullpen.

Southpaw Jake Diekman, who has battled ulcerative colitis since childhood, underwent surgery earlier this week to remove his colon. He is up and moving around already:

24 hours out from getting my entire colon removed! Up to walk today and feeling pretty good. Got to eat 5 bites of mashed potatoes so that was pretty dece! Thanks everyone for the thoughts and prayers, it really helps hearing your success stories and well wishes. Long road ahead but I'm up for the challenge 💪🏽 #gutitout #nocolonstillrollin A video posted by Jake Diekman (@jakediekman41) on Jan 26, 2017 at 9:12am PST

Ulcerative colitis is a disease that causes inflammation and ulcers in the digestive tract. Diekman has been open about his disease, and is involved with the Crohn's and Colitis Foundation of America.

According to Gerry Fraley of the Dallas Morning News, Diekman hoped to delay the surgery until next offseason, but a flare-up over the holidays forced him to have the procedure now. From Fraley:

"It's one of those step-away-from-baseball deals," [GM Jon] Daniels said. "I know he's a big-time competitor and is not looking forward to being away from the club. From a competitive standpoint, you hate to lose someone like him, but this is the right thing to do."

Diekman, 30, came over from the Phillies in the Cole Hamels trade. He has a 3.01 ERA (148 ERA+) with 79 strikeouts in 74 2/3 innings with the Rangers since the trade.

With Diekman out, Texas skipper Jeff Banister figures to rely on Alex Claudio as his primary lefty reliever.