The Donegal defender was making just his second appearance in nine months since breaking his leg back in March, but was replaced at half-time by Johnjoe Kenny.
"Seamus will go for a scan tomorrow".
The home win was secured through goals from Gylfi Sigurdsson, Oumar Niasse and Tom Davies.
Palace pulled a goal back after Luka Milivojevic converted a 83rd minute penalty following a handball inside the box by an Everton player.
Having managed previously at Porto after spending a number of years as a player there, Fonseca has gone from strength to strength in management and was the named coach of the year in 2016/17 in Ukraine's top-flight. Palace are 14th with 27 points.
'True American heroes': Police identify 2 officers fatally shot in Ohio
Officer Morelli was recognized in 2012 as the Westerville Division of Police Officer of the Year. The officers responded after police received a 911 call and the caller hung up.
The substitute's spot-kick was brilliantly saved by Mat Ryan - and moments later another replacement, Anthony Knockaert, headed Mame Diouf's effort off the line to preserve Brighton's hard-earned point.
The Seagulls had taken a first-half lead through a clinical finish from Colombia winger Jose Izquierdo before the 18th-placed Potters, who remain in the bottom three on goal difference, levelled through a curling effort from Switzerland global Xherdan Shaqiri 22 minutes from time.
And at the Liberty Stadium, Swansea continued their resurgence under new manager Carlos Carvalha as they pipped Burnley 1-0.
And with the points sealed, Sam Allardyce drafted on his French midfielder for the remaining 10 minutes though to the frustration of the home fans who booed his introduction.
Defeat for Sean Dyche's Clarets leaves them 10 games without a league victory, although they stay seventh.
The Hammers are now 12th on 30 points with Watford 11th also on 30 points.