Zach Jackson was summoned from Triple-A and will make Wednesday's start. (Getty Images)

CLEVELAND -- The Indians' rotation situation has become so cloudy that the club didn't announce Wednesday's starter until after Tuesday's game.

The mystery is over. Left-hander Zach Jackson is getting the call from Triple-A Columbus.

Jackson will take the 25-man roster spot of left-handed reliever Rich Rundles, who was optioned back to Columbus after Tuesday's 5-1 win over the Rays.

This will be Jackson's second stint with the Tribe. He opened the season in its bullpen as a long reliever before getting sent down to Columbus on April 22. While with the Clippers, he was stretched back out to starting duties and went 3-2 with a 3.09 ERA in seven appearances, including four starts. He struck out 13 and walked eight in 23 1/3 innings.

Jackson, acquired in last summer's trade that sent CC Sabathia to the Brewers, made nine starts for the Tribe down the stretch last season. He went 2-3 with a 5.60 ERA.

Rundles has had two stints with the Tribe this year, with only one appearance. He gave up one hit and let two inherited runners score in one inning against the Rays on Monday.