Brian McDermott is "absolutely certain" Sam Byram will be at Leeds next season, despite interest from a host of Premier League clubs.
Manchester City, West Brom and Cardiff City had Byram on their watch-list in January, while Norwich are also believed to be monitoring his progress having lured Bradley Johnson, Jonny Howson, Robert Snodgrass and Luciano Becchio to Carrow Road from Elland Road.
The 19-year-old Byram had a stellar season for the Whites and is set to make his international debut with England's Under-20s next month.
But McDermott is confident he can hang on to the right-back, who is rated in the ?8million bracket after penning a contract extension until 2016.
The Leeds boss told the Yorkshire Evening Post: "Sam wants to be here next season and the club want him to be here next season. I'm absolutely certain of that.
"If someone does try to push him in a different direction then it won't be the player or the club who are doing the pushing. I'm not concerned about it.
"For me his development as a player will be so much better and quicker through regular football, and the games he's had at Leeds have done him the power of good.
"You can see that he's loving it and I feel very strongly that he's in the right place. I know he thinks so, too. Why would he want to go anywhere else?"
Firmino netted in the 11th and 29th minutes to give the home side an ideal start.
Mohamadou Idrissou scored an away goal for the second division side in the 58th minute, but substitute Sven Schipplock added a third for Hoffenheim nine minutes later.
The return leg will take place on Monday.
Hoffenheim had needed a dramatic 2-1 win at Champions League finalists Borussia Dortmund on the last day of the regular season to give themselves a shot at the play-off and they were on the back foot early on.
Kaiserslautern, who have never beaten Hoffenheim in seven competitive matches, had the first chance after five minutes, but Hoffenheim goalkeeper Koen Casteels made a superb stop to deny Erwin Hoffer from 12 yards.
And the hosts grabbed the lead six minutes later, Sejad Salihovic sending in a free-kick from the right side to Firmino, who was quicker than his marker and easily struck home.
Hoffenheim doubled their lead when Kevin Volland fed a charging Andreas Beck, who crossed from the right to the far post for Firmino to convert.
Lautern had a chance three minutes before the break, but Hoffer's volley from eight yards was sliced over the bar.
The visitors were more clinical in the 58th minute and halved the deficit when Hoffenheim lost the ball in midfield, Alexander Baumjohann played in Idrissou and he rounded Casteels and to score.
Hoffenheim nearly scored a third three minutes later, but Stefan Thesker's header went just over the bar.
But number three did arrive in the 67th minute as Schipplock, who had only been brought on two minutes earlier, won the ball off Marc Torrejon, played a one-two with Firmino and then clipped his finish past Lautern keeper Tobias Sippel.
The hosts almost added a fourth soon after, but Fabian Johnson headed over from three yards.
The Deventer club have already denied Volendam promotion once this season, beating them 3-1 on the final day of the regular season and allowing Cambuur Leeuwarden to snatch the Eerste Divisie title.
And they were in the mood to inflict further punishment as Xander Houtkoop put them ahead in the eighth minute this evening.
They had to wait until the last 20 minutes to add to their lead, Jarchinio Antonia doing the honours.
And after Volendam had Paul de Lange sent off, Marnix Kolder made it three to all but seal Go Ahead's promotion ahead of Sunday's return leg.
Sparta Rotterdam earned a 0-0 draw at home to Roda JC, denying the top-flight side an important away goal.
Donovan Deekman could even have snatched an advantage for the second-tier side in injury time but was denied by a good save from Filip Kurto.
The 46-year-old has been working as head of sports performance at Fratton Park since his arrival in August 2010 and will continue in that role while working alongside Whittingham.
He told the club's official website: "I've been given the title assistant manager and head of sports performance. That encompasses all medical aspects and the fitness of the players.
"It also involves identifying players for Guy who can take the club forward.
"You can see from those we've signed so far that we're mostly concentrating on players aged between 21 and 26, who also have a resale value.
"We've worked particularly hard on player recruitment since January and we've tried to get ahead of the game and sign players quickly.
"It's a real honour to hold this position and I feel proud and privileged to do it for a club of this size and stature."
Whittingham, who was confirmed as boss last month after a lengthy spell as caretaker, added: "Steve has pretty much been fulfilling the role of assistant manager since January.
"Andy Awford was a huge help on the coaching side, but Steve was doing all the off-field stuff that an assistant manager would do. I was talking to the chairman about how valuable Steve was and he replied that an assistant manager was right under my nose.
"He's the ideal man for the role of assistant manager, which he will combine with his medical duties."
