The Finnish midfielder has joined the MLS Cup holders to fill the gap before the Liverpool captain's summer arrival.
Vayrynen, 33, linked up with the MLS Cup holders during last month’s preseason tour of Europe, where he featured in both friendlies and scored the game-clinching goal in a 1-0 win at Shamrock Rovers.
The Finland international had been out of contract since leaving HJK Helsinki this winter, and is now set to slot straight into the line-up to fill Steven Gerrard’s future spot before the Liverpool skipper’s mid-season arrival.
“Mika is a player that brings additional experience to our midfield,” said Head Coach and General Manager Bruce Arena. “We saw his abilities during preseason and are confident he can contribute to our team this season. We are happy he will be a part of our group going forward.”
Vayrynen’s arrival in LA sees him reunited with former teammate Robbie Rogers, having both been at Leeds together for a brief period in 2012.
Arriving at Elland Road as a free agent in September 2011 after leaving Heerenveen, the former Eredivise star endured a lacklustre seven-month spell with the Championship club, making just 12 total appearances amid a rash of injuries.
His fortunes improved, however, after being released the following April, with the 59-times capped midfielder going on to have three solid seasons back in his native Finland with HJK, where he scored seven goals in 57 games, while continuing to turn out for the national team.
It remains to be seen whether there is a long-term future for him with LA, considering Gerrard’s impending arrival, but he at least has an excellent chance of claiming silverware in 2015, with the Robbie Keane-skippered side the current favourites to claim a fourth league title in five seasons.