| Date | Transaction |
| 02-28-1976 | Cliff Welch has retired from football. |
| 08-05-1974 | The Washington Xenomorphs have moved Scott Grgach and Chad McKalip to the active roster. The Washington Xenomorphs have moved Kwame Pepper and Hessley Brigance to the inactive roster. |
| 08-05-1974 | The Washington Xenomorphs have waived Cliff Welch. |
| 04-28-1974 | The Washington Xenomorphs have acquired Cliff Welch from the waiver wire. |
| 09-09-1973 | The Arizona Bandits have waived Cliff Welch. |
| 12-18-1972 | The Arizona Bandits have moved Cliff Welch and Eric Pureifory to the active roster. The Arizona Bandits have moved Dave Prochaska and Terry Pruitt to the inactive roster. |
| 10-15-1972 | The Arizona Bandits have moved Terry Pruitt and Ken Emanuel to the active roster. The Arizona Bandits have moved Cliff Welch and Hank Brown to the inactive roster. |
| 10-15-1972 | Cliff Welch of the Arizona Bandits is injured with an elbow inflammation and is expected to be out for approximately 8 days. |
| 09-03-1972 | The Arizona Bandits have moved Cliff Welch and John Bell to the active roster. |
| 01-31-1972 | The Green Bay Blizzard have moved Adrian Brooks to the active roster. The Green Bay Blizzard have moved Cliff Welch to the inactive roster. |
| 08-22-1965 | Trade #44353 has been completed between the Washington Xenomorphs and the Green Bay Blizzard. The Green Bay Blizzard receive Rashod Davidson (WR), Cliff Welch (WR) from the Washington Xenomorphs in exchange for Draft Pick - 1968 Round 3 (GB). |
| 08-15-1965 | The Washington Xenomorphs have moved Andre Reynolds, Roy Smith, Tom Sinnott, Willie Spirida, Albert Ray, Cliff Welch, Elmer Isom, John Farley, Ravin Broadhurst, E.L. Ulinski, John Jefferson, Floyd Ryan, Sean Broyles, Don Leary, Dar Smith, Jason Simmons, James Bond, and Oscar Key to the active roster. The Washington Xenomorphs have moved Rick Larden, Joe Robustelli, Mike Hull, Mark Hickman, Doug Parker, Morris Joseph, Leather Al-Jabbar, Brandon Lund, Al Compton, Max Ariail, Jim Lofton, Jeff Zilly, Laron Stewart, Joey McDonald, Larry Herline, Kurt Johnson, Brian Eissler, and Tom Walter to the inactive roster. |
| 01-04-1965 | The Washington Xenomorphs have moved Tony Moriarty to the active roster. The Washington Xenomorphs have moved Cliff Welch to the inactive roster. |
| 12-28-1964 | The Washington Xenomorphs have moved Cliff Welch, Elmer Isom, Tony Moriarty, Tony Frankian, and Pete Burgess to the active roster. The Washington Xenomorphs have moved Kevin Dubzinski, Doug Parker, Sammy Schmit, Johnny Settle, and Rat Howard to the inactive roster. |
| 12-21-1964 | The Washington Xenomorphs have moved Kevin Dubzinski, Max Ariail, Sean Broyles, and Kurt Johnson to the active roster. The Washington Xenomorphs have moved Cliff Welch, Elmer Isom, Tony Moriarty, and E.L. Ulinski to the inactive roster. |
| 11-02-1964 | The Washington Xenomorphs have moved Richard Studdard, Cliff Welch, Elmer Isom, and Mark Hickman to the active roster. The Washington Xenomorphs have moved Tony Moriarty, Dar Smith, Jeff Zilly, and Ryan Mills to the inactive roster. |
| 10-05-1964 | The Washington Xenomorphs have moved Ed Papale, Sean Broyles, Elmer Isom, and Pete Burgess to the active roster. The Washington Xenomorphs have moved Ryan Mills, Joe Currivan, Sammy Schmit, and Cliff Welch to the inactive roster. |
| 09-28-1964 | The Washington Xenomorphs have moved Cliff Welch, Bill Mallory, Jeff Zilly, Ryan Mills, and Joe Currivan to the active roster. The Washington Xenomorphs have moved Pete Burgess, Elmer Isom, Tony Frankian, Mark Hickman, and Ed Papale to the inactive roster. |
| 09-20-1964 | The Washington Xenomorphs have moved Lonnie Rosenthal to the active roster. The Washington Xenomorphs have moved Cliff Welch to the inactive roster. |
| 09-20-1964 | The Washington Xenomorphs have acquired Cliff Welch from the waiver wire. |
| 09-07-1964 | The Seattle Sirocco have waived Cliff Welch. |
| 08-10-1964 | The Seattle Sirocco have moved Troy Walker, Cliff Welch, Ron Buss, and Larry Brown to the active roster. The Seattle Sirocco have moved O.J. Kay, Paul Kirksey, Joe Fowler, and Kynan Raines to the inactive roster. |
Wide Receiver