The pair have both reached four bookings for the season, leaving them perilously close to receiving a one-match ban.
Just one yellow card for either man would lead to him being suspended, and with the Saints squad still recovering from a spate of injuries, and with fixtures coming thick and fast, further absentees are just about the last thing Pochettino needs right now.
But if they can avoid picking up a further caution in the games against Tottenham, Cardiff and Everton, then they pass the five bookings for a ban cut off, with the next target to avoid then being ten by April 13.
Schneiderlin’s fourth booking of the campaign was picked up in the closing stages of the 1-1 draw with Newcastle at St James’ Park.
The French midfielder made his first team return following injury as a second-half sub.
Schneiderlin, right, is a massive player for Saints and Pochettino is sure to want him back starting regularly as soon as possible, and won’t want a suspension once he is up and running again.
The challenge which led to Schneiderlin’s yellow card was the one that which sparked off an unseemly melee in the dugouts with the goalkeeping coach for each club, Toni Jimenez and Andy Woodman, sent to the stands for the remainder of the match.
Saints and Newcastle are waiting to hear whether any action will be taken once the FA have viewed the referee’s report in full.
Fonte was an unused substitute at St James’ Park. He has also been struggling with a knock over the last month or so and Pochettino is trying to manage him carefully.
There is no doubt that his preferred centre half pairing is Fonte and Dejan Lovren but the manager said at the weekend he will not risk players carrying slight knocks.
That is probably a wise move as he can scarcely afford any more players to drop out. Saints already have Artur Boruc, Kelvin Davis, Nathaniel Clyne Danny Fox, Victor Wanyama and Guly do Prado out injured, while Fonte, Schneiderlin and Adam Lallana were deemed unfit to play a full game at Newcastle.
Wanyama is the only other Saints player currently sat on four bookings, but the hairline fracture in his leg which will see him sidelined until early in the new year means there is no chance of him picking up another caution before the cut off point.
Jos Hooiveld and Dani Osvaldo are the only other players that need to heed a little caution as they both have three yellow cards to their name.