Welsh injured his ribs in his first VFL match last weekend after overcoming a two-week groin problem, and the Bombers are now unsure when he will be available.
However, Winderlich will need to prove his fitness at training on Thursday if he is to return from a broken hand.
Coach Matthew Knights said the Bombers’ recent dominance over the Blues would count for nothing when they meet on Friday night at the MCG.
“I think the last six times fills the history books. We haven’t brought the history books out this week,” he said.
“It’s a new contest, a new game. Carlton has had a big week; they’re going to be fierce for the whole four quarters.”
Knights said the Bombers would enter the match with confidence after their past fortnight, which included “excellent” wins over North Melbourne and St Kilda.
He said it was important to continue with that form to erase the three “awful and shocking” losses to Adelaide, Melbourne and West Coast before the triumph over the Kangaroos.
“I think the North Melbourne game gave us real impetus to go into the St Kilda contest,” he said.
“The St Kilda contest allows us to come with a really free mind and play spirited football tomorrow evening, which is what we’re all about.
“We know internally where we’re headed and we understand what’s on our list and what we’re endeavouring to mould and bring together.
“On this season alone, we’ve still got to chip away at getting some respect back.”
Key position prospect Jake Carlisle is a chance to make his debut while captain Jobe Watson is certain to play despite being hampered by calf soreness against St Kilda last week.
“No, not at this moment,” Knights said, when asked if the skipper was in doubt.
“We’ve got to train this morning but there’s no doubt. He’s selected and he’ll be running out first onto the MCG tomorrow night to lead our team into battle.”
Carlton coach Brett Ratten labelled the game as the Blues’ “biggest defining moment of our season so far”, and said it was a partial “line in the sand” game after their insipid performance against Collingwood last week.
Knight was bemused with the “line in the sand” reference, which was the term given to the 2004 clash between the Hawks and Bombers that saw an enormous melee dominate the third quarter.
“The footage of that game is pretty graphic,” he said.
“Carlton-Essendon, 70 or 80,000 people ... we’d love to see all our supporters out there tomorrow night so we can at least win the lion’s share of support in the stadium.
“It will be a huge game. It’s going to be on. I stated a few weeks ago, it’s great for our footy club to be involved in these Friday night clashes.
“As a football club and for the players, you couldn’t ask for more than the experience of being involved.
“We’ve jumped one [Friday night] hurdle and this is the second one on the agenda.”