Mat Latos is scheduled to make another rehab start tonight and reports indicate he’ll be asked to throw 100 pitches. If he feels healthy afterward, it may be his final start before rejoining the Reds. If that’s the case, whose spot will he take in the rotation when he does come back? The choices appear to be Alfredo Simon and Tony Cingrani.

The arguments for Latos replacing Cingrani:

1. Simon has been more effective than Cingrani so far this year, measured by ERA, FIP and xFIP. Cingrani’s strikeout rate is lower than last year and his walk rate is considerably higher. He’s had a hard time developing pitches beyond his fastball. He’s even had trouble this year with consistent command of the fastball.

2. Latos and Cingrani are pitching on the same night, so it would be easy to drop Latos right into that slot.

3. Cingrani could provide the Reds a high-leverage LH arm in the bullpen. Cingrani was a dominant closer in college so he’s used to the bullpen role. His pitch portfolio might be better suited to the bullpen. He could lengthen the number of quality arms in the bullpen. See Chapman, Aroldis.

4. The Reds LH situational relievers have struggled this year. Cingrani could replace Sean Marshall, who might need a trip to the DL. Even Manny Parra has had issues with his control. His walk rate is up from 8% in 2013 to 12% in 2014.

The arguments for Latos replacing Simon:

1. Simon has never pitched an entire season as a starter. It has been three seasons since he’s thrown more than 100 innings. If he continues to pitch as a starter, he could eventually wear down his arm, which might preclude a switch to the bullpen. If he moves to the bullpen now, his innings total for the season would be reasonable.

2. Simon’s underlying numbers (strikeout rate, BABIP, etc.) indicate he’s not really pitching as well as his ERA indicates. The metrics (FIP, xFIP, SIERA) that historically have done a better job of predicting ERA than a pitcher’s current ERA, all point to a major increase in Simon’s ERA. In two of Simon’s last five outings, he’s given up 5 runs in 3 innings.

3. Simon’s flexibility as long reliever is needed to stabilize the bullpen.

4. Cingrani had a promising, if overachieving, partial season as a starter in 2013. He is the Reds sole left-handed starter. The Reds are counting on him as a future low-cost starter. Once he moves to the bullpen, it may become impossible to move him out. See Chapman, Aroldis.

One compromise solution might be to keep Simon in the rotation until the All-Star break, then move him to the bullpen. In the meanwhile, Cingrani stabilizes the high-leverage lefty side of the bullpen while Parra and Marshall develop more consistency. At some point, Cingrani moves back to the rotation for the rest of the season.

What say you, Nation?