Task: Question Answering
Input (English): Passage: Following a life-threatening drug addiction that developed after leaving the Chili Peppers in 1992, Frusciante completed a month of drug rehabilitation at Las Encinas in Pasadena in 1998. Shortly thereafter he was asked to rejoin the band. After several months of writing and recording, the Chili Peppers' next album, Californication was released. The album went on to sell more than 15 million copies worldwide, becoming the Chili Peppers' most successful recording to date. Frusciante's return generated much response from critics, who recognized the album as a commercial revitalization from their previous record, One Hot Minute. A two-year-long, international tour followed, which included several festival appearances, including Woodstock 1999 and Rock in Rio.
The writing and formation of By the Way began immediately following the culmination of Californication's world tour, in the spring of 2001. As with Californication, much of the creation took place in the band members' homes and other practice locations, such as a recording studio stage. Kiedis recalled of the situation: "We started finding some magic and some music and some riffs and some rhythms and some jams and some grooves, and we added to it and subtracted from it and pushed it around and put melodies to it." Frusciante and Kiedis would collaborate for days straight, discussing guitar progressions and sharing lyrics. For Kiedis, "writing By the Way...was a whole different experience from Californication. John was back to himself and brimming with confidence." Prior to recording By the Way, the Chili Peppers decided that they would again have Rick Rubin produce the album. Rubin had, in the past, granted the Chili Peppers creative freedom on their recording material; this was something they thought essential for the album to be unique, and could only occur with his return. 
Question: What was Frusciante asked to rejoin after rehab?
Output (English): the Chili Peppers.