Back
Anderson had to be substituted in the first half of the 2-1 win at Solihull Moors.
And fellow defender Ellis missed the game with a similar problem.
Head coach Rob Elliot suggested neither issue was a serious one but they were likely to miss further games.
Anderson went off in the 27th minute at Solihull after going down feeling his right calf.
“He doesn’t think it’s too bad – he just felt it going,” Elliot told the News & Star.
“We just can't seem to catch a break at the moment.
“Tom hasn't played loads of games but he’s been absolutely superb around the place and with his experience.
“I thought he started the [Solihull] game well. Unfortunately it looks like we might have lost him for a bit.”
Ellis was not in the squad for the victory at the ARMCO Arena, the Cumbrian having also sat out the previous weekend’s FA Cup victory against Tamworth.
Elliot offered an update on the versatile Cumbrian. He said: “Jack felt his calf before the cup game.
“A few days after the previous game [the 0-0 draw with Kidderminster Harriers], he just felt something.
Jack Ellis is sidelined with a calf injury (Image: Richard Parkes)
“Jack’s probably only a week or two away – hopefully he won’t be too far away.”
Another player due to be assessed is attacker Regan Linney, who went off in the closing stages at Solihull.
“Regan whacked his knee,” Elliot said.
“He just seemed to catch his knee and he said he felt something go.
“I don't think it's serious because he walked off, but he's obviously felt something.
“Regan is a pretty robust guy – he's a bit of an anomaly when it comes to the sports science stuff. So hopefully for him it will just settle down and we hope he's OK.”
Elliot was full of praise for Kenton Richardson, who replaced Anderson in the first half at Solihull.
“This is where the squad comes into it, because Kenton has been superb without having had loads of minutes – and he was terrific again.”
There was also a boost for United at Solihull as Luke Armstrong joined in the warm-up as he nears a return to action, having been out since pre-season.