Lucas' absence and Liverpool's subsequent change in formation altered the position of two of Liverpool's key players against Fulham: whoever the holding midfielder is and Luis Suarez.
Jay Spearing often played further up the pitch than Lucas usually defends, while far more static in general. The 4-3-3 formation, with Carroll as center-point and Suarez and Bellamy lurking on either side, meant Liverpool's talismanic Uruguayan took up positions further from goal.
I'm using West Brom away, Stoke away, and Wolves at Anfield as points of comparison in chalkboards below. As said in yesterday's review, I think West Brom is the strongest parallel except in finishing – similar opposition playing style, away from Anfield, and with Carroll and Henderson starting. Stoke away is comparable in result, losing despite domination, while Wolves at home was another where Liverpool's performance disappointed but the side ground out a result due to taking its chances early on. The possession, passing, and shot statistics against Fulham are relatively similar to those against West Brom and Wolves; the result is the same as that against Stoke. If anything, stats from Stoke and Fulham – the two losses – look "better" than those against Wolves or West Brom.
As usual, click on the chalkboards to make them pop-up full size.
The chalkboards and heatmaps against Fulham show Suarez making more of his contributions further from the penalty area, whether deeper centrally or spending more time on the flanks. He attempted the fewest passes from these four matches against Fulham, and his performance is especially disappointing in comparison to that at West Brom – where he won the penalty and set up the second goal.
Suarez was widely known as a wide forward with Ajax before coming to Liverpool, but he's played as an out-and-out striker in almost every match under Dalglish, and is now playing a similar role with Uruguay (see Zonal Marking's Copa America reports, among others). His performance in a three-man front, an admittedly unfamiliar role at Liverpool, left much to be desired.
Update: Should have included take-ons as well. StatsZone chalkboards from Fulham (1 successful, 5 total), West Brom (3 of 6), Wolves (4 of 9), and Stoke (4 of 12).
Unlike in Suarez's case, the amount of passes played seemed less important than the location, so I'm just including the heatmaps. That 40% zone stands out like a Las Vegas neon sign, surprisingly static, and further forward than Lucas usually plays. There was less movement in Liverpool's midfield without the Brazilian, as well as more space between the holding midfielder and back four, allowing more shots from distance than Liverpool regularly permits.
More chalkboards from Spearing at Fulham compared to Lucas against West Brom:
Spearing's tackles all occurred in the center of the pitch and most of his interceptions are in the same zone where 40% of his passes came from. Filling in for Lucas is a weighty burden, and it's a new role without a Brazilian safety net. Lucas partnered Spearing in all ten of the Liverpudlian's starts under Dalglish last season and in three of four prior to Fulham this season; Spearing with Adam in a 4-2-3-1 against Exeter had been the lone exception.
To be fair, Dalglish may have shifted to a 4-3-3 because of the opposition or to try to use Carroll, Bellamy, and Suarez at the same time, rather than because of Lucas' absence. Given how rarely we'd seen the formation – at Spurs was the only other time this season by my count, and that didn't last long; incidentally the only other time Liverpool's incurred a red card this season – some struggles are to be expected. But at the first time the question's asked, it's frightening evidence that Liverpool will miss Lucas Leiva very, very much.