Tottenham Hotspur saw their injury crisis worsen after Brazil international Richarlison limped out of their FA Cup third-round tie with Aston Villa on Saturday evening. The north Londoners are now sweating on the fitness of the 28-year-old striker, who had to be replaced midway through the first half after picking up a suspected hamstring problem.After starting Wednesday’s 3-2 Premier League defeat against Bournemouth on the bench, Richarlison was brought back into the starting lineup as Tottenham looked to secure a morale-boosting victory over high-flying Villa.Having collected just one win from their last six games beforehand, Spurs head coach Thomas Frank was looking to ease the pressure on his position against Unai Emery’s Villains, who are currently third in the Premier League.However, both Richarlison and Spurs’ night got off to the worst start when Argentina midfielder Emi Buendia fired Villa in front after just 22 minutes at the Tottenham Hotspur Stadium. And things soon went from bad to worse when former Everton and Watford forward Richarlison went down with what appeared to be a hamstring complaint just a few minutes later.After receiving treatment from the Tottenham physios, the attacker was unable to continue and was subsequently replaced by Randal Kolo Muani, who was dropped to the bench after starting against Bournemouth.Following Richarlison’s departure, Spurs soon found themselves two-nil down when in-form Villa star Morgan Rogers beat Guglielmo Vicario with a composed left-footed finish in the third minute of additional time at the end of the first half.In an improved second-half display, Tottenham reduced the arrears when Wilson Odobert scored his second goal of the season after 54 minutes. However, as Frank’s men huffed and puffed for an equaliser, they thought they found it when Xavi Simons rounded Marco Bizot and steered the ball into an empty net, only for the effort to be ruled out for offside.And Spurs were then consigned to their 11th defeat of the season as Villa saw out four minutes of stoppage time to record their 13th victory in their last 15 games in all competitions.Speaking after scoring what proved to be the winner, England international Rogers told the BBC: “We were good the first half, second half they came out really well. We had to dig deep and I think we deserved the win in the end.“I feel really good, I’m in a good bit of form, but so are the team as a collective. This was a big test and I think we overcame it really well.”Tottenham will now be praying Richarlison is not on the sidelines for too long as manager Frank tries to combat the club’s mounting injury list. The Dane is currently without midfielders James Maddison, Dejan Kulusevski, Rodrigo Bentancur, Lucas Bergvall and Mohamed Kudus.Spurs were boosted by the return of striker Dominic Solanke, however, who was an 83rd-minute substitute against Villa following a lengthy layoff with an ankle injury. Destiny Udogie, who has also been battling a hamstring problem of late, was named on the bench against Villa.In the build up to the Villa clash, Spurs boss Frank issued an update on Bergvall, Kudus and Kulusevski, saying: “Kudus is unfortunately a bigger one to the tendon in the quad, so that's one where we expect him back after the March international break. “And then the latest on Dejan Kulusevski is that we know it's a complicated injury, if there's one person that can accelerate that, it is Dejan, he's a top pro and got a top mentality."The most important thing is to remove the pain in the knee. Got an injection to help that 10 days ago, we know in three to four weeks if it's settled, and when it's settled hopefully he'll be on the grass and from there we'll see what's happening.”Add GOAL.com as a preferred source on Google to see more of our reportingWhile it remains to be seen whether Richarlison has sustained a serious injury, Tottenham - who were once again booed off the pitch by their supporters following the Villa loss - will look to bounce back against struggling West Ham United in the league on Saturday, 17 January.Meanwhile, Emery’s Villa - who will discover their FA Cup fourth-round opponents in next Monday’s draw - entertain out-of-form Everton in the league six days later.