The Cardinals have not yet determined when they will use a fifth starter in the coming weeks, but they know who will be added to the rotation when they do. Joe Kelly, who held the Cardinals in Friday’s game with five shutout innings of emergency relief, will get the next open start once the Cardinals figure out how to navigate three off days coming in the next nine days. The unusual schedule gives the Cardinals the chance to skip the fifth spot in the rotation for the entire road trip, if desired, or use the open dates to give rookie Shelby Miller a midseason break as well. “We’ve drawn up easily a dozen models already, trying to think of the pros and cons of each,” manager Mike Matheny said. “If there’s a start to be had it will be Joe Kelly’s. We just need to figure out (how) the off days offer some options.” The Cardinals’ immediate move Saturday was to promote righty Michael Blazek from Class AAA to offer a fresh arm in the bullpen. This is Blazek’s second promotion to the majors, but he did not appear in a game last month. Since returning to Class AAA Memphis, the righty has struck out 19 and walked three in 11 2/3 innings while posting a 2.31 ERA. The make room on the roster for Blazek the Cardinals optioned lefty Tyler Lyons to Memphis, where he will join the rotation. Lyons struggled in his final four starts for the Cardinals after going 2-0 in his first two starts. In the second inning of Friday’s loss, Lyons had to be relieved by Kelly after allowing five of seven batters to reach base. Turns out it was a figurative move as well, as Kelly will move into Lyons’ spot in the rotation. “It’s one you don’t ignore,” Matheny said of Kelly’s success in recent long relief stints. “That role doesn’t suit just anybody. I know that’s not what his end goal is — to be that. But he has certainly been extremely valuable to us.” In three of his past seven appearances, Kelly has thrown at least 60 pitches, and in those long-relief outings he’s allowed two runs on 13 hits and struck out 11 in those 13 2/3 innings.Kelly filled in as a starter a year ago and 10 of his 16 starts were at least six innings with no more than three earned runs. He came to spring training as a candidate for the fifth spot in the rotation, which Miller won. His use as a reliever had kept him out of the rotation of starters the Cardinals used to fill openings that brought Lyons and John Gast to the majors.