The Nationals released Knizner on Saturday, Robert Murray of FanSided.com reports.

Knizner has been phenomenal at Triple-A Rochester this season, slashing .382/.516/.500 with 11 RBI and 10 runs scored across 91 plate appearances. The 30-year-old backstop had the ability to opt out of his minor-league deal this weekend, so he'll now enter free agency and presumably pursue a major-league contract, given how well he's done in the minors.

Dingler isn't part of the Tigers' lineup for Saturday's game against Toronto.

Dingler started each of Detroit's last five games, and he'll get a rest day Saturday against Eric Lauer and the Blue Jays. In Dingler's place, Tomas Nido will catch and bat ninth. In 127 plate appearances, Dingler is slashing .270/.299/.434.

Kirk isn't in the lineup for Saturday's game against Detroit.

Kirk will get a day to reset after going 0-for-8 with a strikeout over his last two games. Tyler Heineman will catch for Eric Lauer instead and bat eighth.

Kelly isn't in the lineup for Saturday's game against the White Sox.

Kelly will give way to Miguel Amaya behind the plate Saturday after going 2-for-4 with a double and two runs scored in Friday's win.

Alvarez isn't in the lineup for Saturday's game against the Yankees.

After going 0-for-2 with two walks and a run scored in Friday's series opener, Alvarez will step out of the lineup Saturday to give Luis Torrens a chance to start behind the dish.

Wells isn't in the lineup for Saturday's game against the Mets.

Wells will grab a seat on the bench Saturday after going 0-for-3 with a walk in Friday's series opener. J.C. Escarra will take over behind the plate and bat seventh.

Murphy went 2-for-4 with a solo home run in Friday's win over the Red Sox.

The backstop went back-to-back with Matt Olson in the second inning off Garrett Crochet. It was Murphy's eighth homer in 28 contests this season but his first long ball since April 26, snapping a 12-game drought. With Drake Baldwin surging, Murphy may need to pick up the pace at the plate to avoid losing even more playing time to the rookie.

Kelly went 2-for-4 with a walk, a double and two runs scored in Friday's 13-3 win over the White Sox.

Kelly had cooled down a bit recently after a scorching hot start to year, as he came into Friday's contest batting just .182 with a .593 OPS in May. After the two-hit effort, the veteran catcher is now sitting with a strong .299 average and 1.068 OPS through 28 games overall. Kelly should continue to see plenty of playing time, but more regression is likely on the way based on his career numbers, and Miguel Amaya should remain heavily involved behind the plate for the Cubs as well.

Del Castillo (shoulder) has begun a throwing program, Alex Weiner of Arizona Sports reports.

If all goes well, the Diamondbacks plan to have Del Castillo begin a rehab stint in the complex league next week. He hurt the shoulder in late March and was expected to miss at least one month.

Moreno went 3-for-3 with two doubles, one walk, one RBI and three runs scored in Friday's 8-0 win over the Rockies.

Moreno has a trio of multi-hit efforts over his last six games, going 9-for-25 (.360) with five RBI in that span. The catcher's recent success at the plate is helping him bounce back after a rough second half of April. He's now batting .259 with a .661 OPS, one home run, 10 RBI, 19 runs scored, one stolen base and five doubles over 36 contests. While he is hitting better lately, Moreno is largely struggling even more than usual in the power department, though his contact skill remains his best tool.