Tyler Lyons (knee) could begin throwing off a mound in about two weeks.
Tyler Lyons underwent knee surgery on Tuesday.
Cardinals GM John Mozeliak said Tyler Lyons' injured knee is "not responding as quickly as we hoped."
Cardinals activated LHP Tyler Lyons from the 60-day disabled list.
Cardinals transferred LHP Tyler Lyons from the 15-day disabled list to the 60-day disabled list.
Cardinals GM John Mozeliak acknowledged Tuesday that Tyler Lyons' season "may be in question."
Cardinals manager Mike Matheny acknowledged Wednesday that Tyler Lyons (knee) will be out "several weeks."
Cardinals placed LHP Tyler Lyons on the 15-day disabled list with a stress reaction in his right knee.
Tyler Lyons threw a bullpen session Thursday afternoon at Marlins Park.
Tyler Lyons pitched 4 2/3 scoreless innings out of the pen Friday against the Dodgers.
Tyler Lyons pitched three innings and allowed one run Thursday as the Cardinals edged the Marlins 4-3.
Tyler Lyons said he's making an effort to give up fewer home runs this season.
Tyler Lyons pitched seven shutout innings to beat the Pirates in the second game of Wednesday's doubleheader.
Tyler Lyons is in line to start on Wednesday versus the Pirates in Carlos Martinez's (shoulder) place.