Blazek, 24, will be making his third stint on the Major League roster this season. The rookie has played at three levels this season, going a combined 0-1 with a 1.41 ERA and 9 saves with Springfield (AA) and Memphis (AAA). He has appeared in four games (3.0 IP) for St. Louis.
Butler, a 24-year-old rookie, has also appeared at three levels this year. He is 1-2 with a 2.81 ERA and 8 saves between Springfield and Memphis and has posted a 1.98 ERA in 12 games (13.2 IP) for St. Louis.
Lyons, 25, made six starts for the Cardinals earlier this year, going 2-3 with a 5.51 ERA. Since returning to Memphis in late June, the rookie left-hander has gone 4-0 with a 1.65 ERA (32.2 IP/6 ER) in six starts, working into the 7th inning in all but two of those outings while striking out 37.
His overall season mark at Memphis stands at 6-1 with a 3.00 ERA in 14 games started (87.0 IP) with 75 strikeouts and a .226 opponent's batting average.
Blazek will wear uniform #67, Butler # 65 and Lyons #70.