ENGLEWOOD, Colo. (AP) -- Andre ''Bubba'' Caldwell canceled his vacation plans after the Denver Broncos' season ended last winter, heading instead to a tattered football field near his home in Atlanta to run routes by himself, ear buds and reflections his only companions.
He was determined to avoid a repeat of 2012, when he caught just one pass and was inactive half the time.
''I had a lot of lonely times - on a crappy football field like 300 feet away from my house,'' Caldwell said. ''So, I'd just walk over there, a shoddy field, holes and everything. I'd be out there by myself, headphones sometimes, and I just made sure I pushed myself every day so I don't have to feel this pain and this hurt that I felt every Sunday.''
That's why it stung so much when he saw that Peyton Manning had invited only Wes Welker, Demaryius Thomas and Eric Decker to his offseason workouts at Duke University.
''No invite to duke to run routes and catch passes DAMN right I took it personal...(hash)Motivation (hash)StillGrinding,'' Caldwell tweeted on April 12.
Manning explained upon his return to Denver that Blue Devils coach David Cutcliffe, his college offensive coordinator, told him and his brother, Eli, they could only bring three receivers each to the workouts, ''so I brought my three starting receivers.''
Manning added that he was ''excited to see Bubba's competitive attitude and I hope he turns that into a productive offseason and can be a productive player for us this year.''
He did, and he is.
Caldwell beat out draft pick Tavarres King for the No. 4 receiver job and has already made a bigger impact this season than he did all of last year.
OK, so he's only caught two passes, but they were both big.
He caught one of Manning's record-tying seven touchdown throws in the opener and last week his 38-yard reception was the longest of the day for Manning and revved up Denver's high-octane offense for another banner afternoon.
Caldwell also walled off two tacklers as punt returner Trindon Holliday weaved his way upfield for an 81-yard touchdown.
Last year, Caldwell was the forgotten man in Denver's offense largely because he wasn't a major special teams contributor.
''If you're not a starter, the only way to make sure you're active on game days is to be on special teams,'' said Caldwell, noting that his offseason workouts helped him get a foothold on the punt return and punt coverage units this season.
Caldwell, who left the University of Florida as the school's all-time leader in receptions, had a decent four-year stint in Cincinnati before joining the Broncos as a free agent last year. But after catching just one pass for 18 yards, he retreated to his offseason home determined to carve out a bigger role.
''Every day I used to come to work and give everything I had but to be inactive on game day was tough on me,'' Caldwell said. ''I used to tell my wife every day I'm going to do whatever I can this offseason to make sure I'm never in that position again.''
So, he nixed his usual monthlong respite from football.
''As soon as I got home, I felt fresh because I didn't really play,'' he said. ''I went straight into training, working every day like it was the middle of the season so I could never be in that position again.''
The snub from Manning drove Caldwell to develop a better rapport with his quarterback, too.
''We never had a talk about it,'' Caldwell said. ''I think he understood where I was coming from. I had no hard feelings against him, just expressing my frustration. I wanted to be a part of everything the team's doing. We understood each other and we just saw past that and we worked hard together every day. And he knew I wanted to be a part of this offense.''
That determination has given Manning yet another target, one whose speed can exploit defenses trying to pigeonhole him into dinking and dunking his way downfield all the time.
''Peyton and I have a connection now,'' Caldwell said. ''And I'm out there on Sundays.''
Just as he envisioned during all those lonely winter workouts on that run-down field by his house.
AP NFL website: www.pro32.ap.org
Follow AP Pro Football Writer Arnie Melendrez Stapleton on Twitter: http://twitter.com/arniestapleton