[2] Wettberg spent his playing career exclusively with Bavarian amateur clubs, eventually becoming player coach of SV Saal.
He entered the top league of Bavarian football for the first time in 1980, when he took over as manager of MTV Ingolstadt, the club just having been relegated from the 2.
He coached local rival ESV Ingolstadt after this, a club that had just dropped from the second to the fourth division in two seasons.
After a brief stint at Jahn Regensburg in 1992, he returned to SpVgg Landshut from 1992 to 1993, the club winning promotion back to the Bayernliga then.
Wettberg coached FC Augsburg in the Regionalliga Süd from July 1995 to September 1996 before returning to SG Post/Süd.
The Jahn, a club in decline since the mid-1970s, experienced a revival under Wettberg, first winning the Landesliga Bayern-Mitte in 1999 and then taking out the Bayernliga title the year after and earning promotion to the Regionalliga.
From there, he went to TuS Regensburg, also in the Landesliga, and managed to take them to second place in the league, his last coaching engagement for the time.
[2] In April 2009, Wettberg returned to managing, taking over SV Seligenporten, a team which had not won a game in seven months and sat on a relegation rank.
[5] Wettberg successfully took Seligenporten into the Regionalliga Bayern, stepping down from his role at the end of the 2012–13 season to take up coaching at amateur club ATSV 1871 Kelheim.