Anderson was the pick of the England attack on day two of the first Test against Sri Lanka but left the field twice for treatment having suffered stiffness in the back and side and only bowled one over in the evening session.
He later re-emerged as nightwatchman as England reached stumps on 47-1 in reply to the tourists’ 400 all out, but England remain concerned about his readiness to bowl.
“Obviously it’s a huge concern for us,” said Broad, who experienced side problems of his own that contributed to his departure from the World Cup earlier this year.
“He felt a bit of tightness in the back and side. Obviously, I know what side injuries are all about after this winter and when you get a little bit of pain it’s not great.
“We’re being cautious. He’s going to go and get a scan this evening and hopefully that will come back clear and he’ll be okay to go because he’s a hugely vital bowler for us. Touch wood he’ll be okay.”
Broad does not believe Anderson’s batting duties this morning will aggravate the injury whatever the results of the medical assessment and expects him to play a frustrating role, as he did when saving the game here against Australia in 2009.
“It is one of the frustrating injuries as a bowler. Hopefully it will just be a little tightness,” added Broad. “Jimmy is not feeling pain when he’s batting and hopefully he’ll have one of those frustrating hours when he wears a few but gets it away.
“With my side injury I could do pretty much everything but bowl. An extensive pull shot might strain it or something but we don’t really see Jimmy playing a huge amount of them, he’s more of a clip to fine leg man.”
Broad, 24, brought up the significant milestone of 100 Test wickets when he removed Thisara Perera, becoming the second youngest England player to do so after Ian Botham.
He preferred not to dwell on the achievement for long, instead focusing on England’s prospects of winning the match from a difficult position.
“I felt in really good rhythm to be honest,” he said. “I’d prefer it to have come at 90-1 not 300-and-odd for eight to be honest but it was hard work out there.
“I actually thought we bowled pretty well and stayed together. It would have been easy to get quite ragged in the afternoon but we did pretty well, created chances and had four or five pretty decent lbw shouts and a few nicks that didn’t go to hand.”
Using Australia’s performance two years ago as a template, Broad insisted a home win was still possible at the SWALEC Stadium.
“I think we’re in a pretty good position. if we can bat big and bat once we have a chance of winning this Test match,” he said.
“We got 435 against Australia in 2009 and we were under the pump for the last 120 overs.”