Sanmartin (elbow) has produced a 5.40 ERA, 1.35 WHIP and 3:2 K:BB in 6.2 innings over his seven relief appearances since being activated from Triple-A Louisville's 60-day injured list July 25.

Sanmartin (elbow) was assigned to the rookie-level Arizona Complex League on Tuesday to start a rehab assignment, Charlie Goldsmith of The Cincinnati Enquirer reports.

The Reds confirmed that Sanmartin (elbow) underwent season-ending Tommy John surgery July 7, MLB.com reports.

The Reds transferred Sanmartin (elbow) from the 15-day injured list to the 60-day injured list Sunday, Paige Leckie of MLB.com reports.

The Reds placed Sanmartin on the 15-day injured list Tuesday, retroactive to May 8, with a left elbow stress reaction.

Sanmartin departed Sunday's appearance versus the White Sox due to left elbow soreness, Charlie Goldsmith of The Cincinnati Enquirer reports.

Sanmartin (1-0) earned the win Tuesday against the Rangers, picking up a strikeout in a clean eighth inning.

Sanmartin was recalled by the Reds on Monday, Charlie Goldsmith of The Cincinnati Enquirer reports.

Sanmartin (0-4) had another nightmare start Sunday, giving up six runs on six hits and two walks while recording only two outs. After the game, Sanmartin was optioned to Triple-A Louisville, Bobby Nightengale of The Cincinnati Enquirer reports.

Sanmartin (0-3) took the loss to the Padres on Tuesday, allowing nine earned runs on eight hits and one walk over three-plus innings. He struck out two batters.