Question: The 2010 Washington Redskins Trent Williams was considered one of the best tackle prospects available for the 2010 NFL Draft, who was the Head Coach of the team at that time?

Context paragraphs:
Zebrie Sanders: Zebrie Sanders (born December 4, 1989) is a gridiron football offensive tackle.  He played college football for the Florida State Seminoles.  He was drafted by the Buffalo Bills in the fifth round of the 2012 NFL Draft.  He was considered one of the best offensive tackle prospects for the 2012 NFL Draft.

Trent Williams: Trent Williams (born July 19, 1988) is an American football offensive tackle for the Washington Redskins of the National Football League (NFL).  He played college football at Oklahoma, and was recognized as an All-American.  He was considered one of the best tackle prospects available for the 2010 NFL Draft, and was drafted fourth overall by the Redskins.

2010 Washington Redskins season: The 2010 Washington Redskins season was the 78th season for the team in the National Football League (NFL), and their first under new head coach Mike Shanahan, who also began his term as the team's Vice President of Football Operations.  The Redskins obtained the 4th pick in the 2010 NFL Draft as a result of their 4–12 record from their previous season, which they used to draft Oklahoma tackle Trent Williams.  Finishing the season 6–10, the Redskins improved on their 4–12 record from the 2009 season, but were officially eliminated from postseason contention in Week 14.  Of the 16 games of the season, only four (all losses) were decided by more than a single possession.

Marcus Cannon: Marcus Darell Cannon (born May 6, 1988) is an American football offensive tackle with the New England Patriots of the National Football League.  Prior to the 2011 NFL Draft, Cannon was considered one of the top offensive tackle prospects and was selected by the Patriots in the fifth round with the 138th pick of the draft.  He played college football at Texas Christian University.

Michael Brockers: Michael Seth Brockers (born December 21, 1990) is an American football nose tackle for the Los Angeles Rams of the National Football League (NFL).  He played college football at LSU.  He was considered to be one of the best defensive tackle prospects in the 2012 NFL Draft, where he was drafted by the Rams in the first round.

Rico McCoy: Rico McCoy (born November 6, 1987) is an American football linebacker who is currently a free agent.  He played collegiate football with the Tennessee Volunteers and was considered one of the best linebacker prospects available for the 2010 NFL Draft, drawing comparisons to Derrick Brooks.  Not selected by any team, McCoy was picked up after the draft by the Buccaneers as an undrafted free agent.

Sergio Render: Sergio Orlando Render (born September 13, 1986) is a former American football guard who played college football at Virginia Tech.  He was considered one of the top prospects available in the 2010 NFL Draft, but was not selected by any team.  Render was picked up after the draft by the Tampa Bay Buccaneers as an undrafted free agent, but was released after the team signed Keydrick Vincent.

Billy Winn (American football): William Jesse Winn, Jr. (born April 15, 1989) is an American football defensive end for the Denver Broncos of the National Football League (NFL).  He played college football at Boise State.  He was considered one of the best defensive tackle prospects for the 2012 NFL Draft and was drafted in the sixth round by the Cleveland Browns.

Joe Pawelek: Joseph Charles Pawelek (born December 8, 1986) is a former American football linebacker who played for the Seattle Seahawks of the National Football League.  He was considered one of the top linebacker prospects available for the 2010 NFL Draft.  He graduated from Smithson Valley High school, coached under Larry Hill.  He played college football for Baylor.

Andre Johnson (offensive lineman): Andre T. Johnson (born August 25, 1973) is a former American football offensive tackle in the National Football League for the Washington Redskins (1996), the Miami Dolphins (1997), and the Detroit Lions (1997–1998).  He played college football at Penn State University and was selected in the first round of the 1996 NFL Draft by the Washington Redskins, who were looking for a replacement of their aging tackle Jim Lachey.  In his NFL career Johnson only played three games, each for the Lions and is usually considered to be one of the worst first round picks of all time.

Supporting paragraphs: 2010 Washington Redskins season Trent Williams
Answer: Mike Shanahan