BUFFALO, N.Y. -- - Sabres starting goalie Linus Ullmark will miss at least the next month with a lower-body injury, leaving Buffalo with one established netminder.

Captain Jack Eichel will also miss his second game but remains day-to-day with a lower body injury, coach Ralph Krueger said before Buffalo hosted the Philadelphia Flyers on Saturday.

Veteran backup Carter Hutton will take over and start both games of Buffalo's weekend series against the Flyers, with minor league call-up Jonas Johansson serving as backup.

High-priced forward Jeff Skinner, however, is set to return after being a healthy scratch for the past three games. Defenseman Rasmus Ristolainen will play 3 1/2 weeks after testing positive for COVID-19 and spending two weeks in the NHL's coronavirus protocol.

Forward Tobias Rieder will return after missing two games with an upper-body injury.

Krueger wouldn't reveal details of Ullmark's injury in calling it "a huge loss."

Ullmark was shaken six minutes into a 4-3 overtime loss to New Jersey Devils on Thursday. He continued playing and stopped all 15 shots in the first period and did not return for the second period.

Ullmark has a 5-4-2 record and was coming off a 41-save outing in a 4-1 win at New Jersey on Tuesday.

Eichel was a late scratch after participating in pregame warm-ups on Thursday.

Skinner's return comes amid questions of whether he and Krueger see eye-to-eye while the 11th-year player and seven-time 20-goal-scorer is in the midst of a slump.

In the second season of an eight-year, $72 million contract, Skinner has one assist in 14 games this season, and not scored in 18 games dating to last season.

"Hopefully, this proves to be a good little regroup to launch and excellent rest of the season for Jeff," Krueger said.

Ristolainen had a severe bout with COVID-19 in which he experienced chest pains and fatigue. He will bolster a blue-line group that lost Jake McCabe (right knee) and Will Borgen (broken right forearm) this past week.