White, who on Monday was named in the 44-man British & Irish Lions touring squad, has been battling with a 'stinger' - an injury initially suffered whilst on Six Nations duty with England in early February. He will join fellow Lions tourist Graham Rowntree and England A hooker George Chuter in the front row.
Ben Kay, another player injured whilst on test duty for England, has been named in the second row, subject to a late fitness test. Kay, who injured his ankle against Scotland on March 19, suffered another setback at training on Wednesday, just two days after also being named in the Lions squad.
"Julian will definitely be starting," said Tigers head coach John Wells on Thursday. "Ben, unfortunately, injured his ankle at the end of yesterday's session. He had a good session, until re-injuring himself, and he wasn't able to train today, leaving some doubt over his participation for this weekend. He'll have another run on Saturday and if he gets through that he'll be fine, if not, he could still come into contention for the Toulouse match."
On White's welcome return from injury, Wells added: "All he needed was time, as you do with most injuries, but I think it's a great boost to the squad. I think we've done the right thing with Julian, although we do have a very capable replacement in Darren Morris."
In further selection news up front, Lions squad members Neil Back and Lewis Moody swap places between the replacements' bench and the No.7 shirt respectively, with Moody - a try-scorer last week - joining fellow back row Henry Tuilagi on an extended bench. (The bench will be trimmed to seven before Sunday.)
In the backline, veteran Austin Healey - who was due to start on the wing, before injury intervened - misses out, with Alesana Tuilagi starting his second successive match, and Geordan Murphy replacing Tom Varndell on the other wing. Sam Vesty returns at full back, having joined the fray from the bench last Saturday.
"Austin's got the same problems as he's had all season," said Wells. "We tried to give him an opportunity to prove his fitness ahead of next weekend, but now he could struggle to make it back for the next week."
In further backline news, England No.9 Harry Ellis returns at scrum-half, with Scott Bemand dropping back down to the bench, whilst centres Ollie Smith and Leon Lloyd, both of whom have not trained because of various injury niggles, have been named amongst the replacements. Youngster Matt Cornwell, who was so impressive off the bench earlier this season, returns to the starting line-up - at outside centre - for his second-ever Tigers start.
"Ollie and Leon haven't trained this week because of injuries," explained Wells. "They could still come into contention for a place on the bench, but Matt's trained well and he's looking forward to a start. He played very well on Monday night in the A League Final and we're all delighted that he's come back from the England Under-21 set-up and started with us where he left off."
And on facing Saracens, who lost 24-45 to London Wasps in High Wycombe last weekend, Wells commented: "It would've taken a good performance by Wasps to get on top of Saracens and to their credit; they came away with a good win. Saracens had to play Wasps away, which is always difficult, but the fact that they scored three tries tells us that they're a threat anyway.
"They'll want to put things right at their place, after we beat them at Welford Road last time out, but we know we're capable of beating them if everything works for us on the day. There are some great battles going on at the top of the league, and some even better ones at the bottom, but we're looking no further than this Sunday. It's as simple as that."