Nido underwent a debridgement on his right knee Tuesday, Maddie Lee of the Chicago Sun-Times reports.

Nido landed on the 10-day injured list last week with a sprained knee and has now had it scoped. He's expected to be sidelined for 4-to-6 weeks, per Andy Martinez of Marquee Sports Network, so he'll likely be out until September.

Maile (back) was sent to Triple-A Louisville to begin a rehab assignment Tuesday.

The 33-year-old landed on the shelf in early July with a herniated disc and was hoping to return just after the All-Star break, but his absence is now approaching a month. Maile still shouldn't require a lengthy rehab assignment, so he could be back with the Reds within the next week.

Alvarez (shoulder) is out of the lineup for Tuesday's game against the Twins, Anthony DiComo of MLB.com reports.

Alvarez is dealing with shoulder soreness in his non-throwing arm and will be held out of the lineup for a second consecutive game. Luis Torrens will catch and bat eighth Tuesday.

Torrens went 3-for-4 with a walk, a double, a run scored and three RBI in Monday's rout of the Twins.

Getting the start behind the plate and batting eighth with Francisco Alvarez nursing a sore shoulder, Torrens did most of his damage with a two-run double in the seventh inning. Alvarez isn't expected to miss much action, but Torrens has demonstrated he's more than capable of filling in should the Mets decide their starting catcher needs a bit more time off. Through 72 plate appearances since joining the team, Torrens is slashing .308/.361/.538 with six doubles, three homers and 13 RBI.

Grandal went 1-for-4 with a solo home run in Monday's 5-3 win over the Astros.

Grandal got the Pirates on the board with a sixth-inning solo shot. He's hit two of his four homers in July, going 6-for-29 (.207) over 10 contests this month. The catcher has a poor .184/.221/.319 slash line with 18 RBI, 12 runs scored and one stolen base over 150 plate appearances. Barring a drastic improvement in performance, Grandal figures to remain in the backup catcher role behind Joey Bart.

Murphy went 1-for-4 with a solo home run in Monday's 8-3 loss to Milwaukee.

Murphy's playing time has been dropping in the second half -- he's gone just 3-for-15 with five walks over five games since the All-Star break. The catcher's homer came in garbage time Monday. He's up to six long balls, 13 RBI, 10 runs scored, three doubles and a .210/.295/.379 slash line through 38 contests this season. Until Murphy finds more consistency at the plate, Travis d'Arnaud will continue to eat into his playing time.

D'Arnaud is out of the lineup for Monday's game against the Brewers.

Though he'll be on the bench Monday, d'Arnaud had started at catcher in three of the past four games and may have moved into a near-even timeshare with Sean Murphy. D'Arnaud is currently in the midst of a seven-game hitting streak, during which he's slugged two home runs and has drawn three walks. Murphy, meanwhile, has gone 2-for-19 with no extra-base hits over his last seven games, with his struggles prompting manager Brian Snitker to increasingly favor the hotter bat of the two catchers.

Mets manager Carlos Mendoza said Alvarez is absent from Monday's lineup versus the Twins due to left shoulder soreness, Tim Healey of Newsday reports.

Mendoz said Alvarez will be available off the bench, though he would prefer to give his top catcher the full day off before returning him to the lineup Tuesday. Luis Torrens will draw the start behind the dish Monday.

The Reds placed Wynns on the 10-day injured list Monday with a right teres major tear.

Per Charlie Goldsmith of The Cincinnati Enquirer, Wynns sustained the injury at some point in Sunday's 2-1 loss to the Rays, which may explain in part why Tampa Bay went 4-for-4 on stolen-base attempts while the catcher was behind the dish. Even if Wynns doesn't require surgery to address the injury, he'll likely be sidelined for beyond the minimum 10 days, and he could even be at risk of missing the rest of the season. The Reds called up Eric Yang from Triple-A Louisville to replace Wynns on the active roster as the backup to No. 1 catcher Tyler Stephenson.

Contreras went 1-for-4 with a solo home run in Sunday's 4-3 win over the Nationals.

Contreras opened the scoring with his first-inning blast off Washington starter DJ Herz. This was Contreras' second game in a row with a homer, and he's gone deep three times over nine contests since the All-Star break. The steady catcher is up to 13 long balls, 29 RBI, 37 runs scored and three stolen bases while slashing .274/.394/.519 through 60 games this season.