Taking over for injured pitcher Cole Hamels, Lee will be making the second opening-day start of his career and first since 2009 for Cleveland.
The 35-year-old Lee pitched five shutout innings Saturday against Boston and has a 2.63 ERA in four spring training games.
''Easy call,'' manager Ryne Sandberg said. ''Obvious reasons. An All-Star last year. The way he's pitched this spring. Easy call.''
Sandberg announced the news after the Phillies' game against Baltimore was canceled because of rain.
Yu Darvish is slated to start the opener for Texas.
''It's definitely an honor,'' Lee said. ''I look forward to it. I'm ready to go. It's coming on us pretty quick. It's two weeks away, so I'm ready to go.''
Lee is entering the fourth season of a $120 million, five-year deal. He was 14-8 with a 2.87 ERA in 31 starts last year, when he made his fourth All-Star team.
The 2008 AL Cy Young Award winner in 2008, Lee has gone 85-50 with a 2.89 ERA, 25 complete games and 12 shutouts in 186 starts during the last six seasons.
Sandberg said veterans A.J. Burnett and Kyle Kendrick will follow Lee in the rotation.
''We look good,'' Lee said. ''Obviously Cole being injured isn't good, but we get him back and we're going to be pretty strong. Health is the key to everything. If we stay healthy and continue to go out there then we'll be a solid chance and give the team a chance a lot.''
Slowed by biceps tendinitis, Hamels threw a bullpen session Sunday, his second in five days. Hamels may not rejoin the rotation until May.