MacDonald, 29, has appeared in 76 NHL games with Florida and Colorado, posting 12 points (two goals, 10 assists) and 21 penalty minutes.
A defenseman who also plays the forward position, he has also played in 271 American Hockey League (AHL) games with Springfield, Albany, Binghamton and Colorado, collecting 189 points (68 goals, 121 assists) and 123 penalty minutes.
MacDonald was named to the AHL First All-Star Team in 2018 and the Second All-Star Team in 2020. He was also named to the 2020 AHL All-Star Game as a member of the Colorado Eagles.
The six-foot, 204-pound native of Portland, Oregon, originally signed as a free agent with Florida in 2018, and played collegiately for four seasons at Cornell University.
"Jacob is a versatile veteran player who has been an All-Star at the American Hockey League level and will add depth to our NHL line-up," said Grier.
Kaut, 23, has split time with the Avalanche and the Colorado Eagles (AHL) this season, recording three points (one goal, two assists) in 27 NHL games and eight points (five goals, three assists) in 10 AHL appearances. Last season, Kaut amassed 31 points (19 goals, 12 assists) in 46 regular season games with the Eagles and added five points (one goal, four assists) in nine playoff games. The winger finished third on Colorado in regular season goal scoring and his goal and point totals established new career highs.
In 173 AHL games, Kaut has registered 99 points (47 goals, 52 assists) along with 103 penalty minutes. In 47 NHL games, he has posted six points (three goals, three assists) and 10 penalty minutes.
Prior to making his North American debut in the 2018-19 season, Kaut spent the 2017-18 season with HC Dynamo Pardubice of the Czech Extraliga, where he tallied 16 points (nine goals, seven assists) in 38 games. His point totals that season are the fourth most by an NHL Draft eligible player, with new teammate Tomas Hertl's 2011-12 campaign (25 points) ranking second.
Internationally, Kaut has represented the Czech Republic at the junior and senior levels. He appeared at the 2018 and 2019 World Junior Championships, where he totaled seven points (two goals, five assists) in seven games and four points (three goals, one assist) in five games, respectively.
The six-foot-two, 190-pound native of Brno, Czech Republic was originally selected by Colorado in the 2018 NHL Draft (first round, 16th overall).
"Martin is a former first round pick who bolsters our group of young developing forwards at the American Hockey League level," said Grier. Nieto departs the Sharks after tallying 15 points (eight goals, seven assists) in 45 games this season. In his most recent stint with San Jose, which began with the 2020-21 season and spanned 143 games, the Long Beach, California, native finished with 19 goals and 20 assists. In 364 career games with San Jose, Nieto posted for 109 points (47 goals, 62 assists).
Merkley appeared in 39 games with the Sharks in 2021-22 and posted six points (one goal, five assists). With the San Jose Barracuda of the American Hockey League this season, the defenseman recorded 14 points (all assists) in 30 contests. In 93 career AHL games, Merkley has two goals, 42 assists and 70 penalty minutes.
